This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow P3Rs: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when P3Rs are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow E-mail this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My File Cabinet
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via ISI Web of Science (15)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Gravholt, C. H.
Right arrow Articles by Christiansen, J. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gravholt, C. H.
Right arrow Articles by Christiansen, J. S.
Related Collections
Right arrow Endocrinology

PEDIATRICS Vol. 110 No. 5 November 2002, pp. 889-896

Short-Term Growth Hormone Treatment in Girls With Turner Syndrome Decreases Fat Mass and Insulin Sensitivity: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study

Claus Højbjerg Gravholt, MD, PhD*, Rune Weis Naeraa, MD*,{ddagger}, Kim Brixen, MD, PhD§,||, Knud William Kastrup, MD, Leif Mosekilde, MD, DrMedSci§, Jens Otto Lunde Jørgensen, MD, DrMedSci* and Jens Sandahl Christiansen, MD, DrMedSci*

* Medical Department M (Endocrinology and Diabetes) and Medical Research Laboratories, Aarhus Kommunehospital, Aarhus University Hospital, Aarhus, Denmark
{ddagger} Pediatric Department, Skejby Sygehus, Århus University Hospital, Aarhus, Denmark
§ Department of Endocrinology C, Aarhus Amtssygehus, Aarhus University Hospital, Aarhus, Denmark
|| Department of Endocrinology M, Odense University Hospital, Odense, Denmark
Pediatric Department, Copenhagen County Hospital, Glostrup, Denmark

-->
   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 METHODS
 RESULTS
 DISCUSSION
 CONCLUSION
 REFERENCES
 
Background. Most girls with Turner syndrome (TS) receive growth hormone (GH) treatment during childhood and adolescence, but controlled data on the effects on body composition and glucose metabolism are lacking.

Objective. To study the effects of GH treatment on insulin sensitivity, glucose metabolism, bone turnover, and body composition.

Methods. A randomized, placebo-controlled, crossover study was conducted with girls with TS. All girls with TS were treated with GH 0.1 IU/kg/d subcutaneously at bedtime or with placebo for 2 months and studied at the end of each period. Control subjects were studied once without treatment. Twelve girls with TS, aged 9.5 to 14.8 years (median: 12.9 years) and 16 age-matched control subjects (10.3–16.0 years; median: 12.1 years) were studied. Twenty-four-hour sampling of blood was performed; GH, insulin-like growth factor I (IGF-I), IGF binding proteins (IGFBPs), insulin, glucose, and lipolytic and gluconeogenic precursors were assayed, followed by an oral glucose tolerance test. Body composition was evaluated by dual-energy x-ray absorptiometry scanning and body mass index (BMI). Fasting bone markers were measured.

Results. Height was reduced in TS as compared with control subjects. In the placebo situation, 24-hour integrated GH as well as IGF-I was significantly reduced in girls with TS compared with control subjects. Controlling for differences in lean body mass (LBM; or fat mass [FM]) and sexual development did not explain the difference in 24-hour integrated GH. Differences in sexual development, BMI, FM, insulin sensitivity, and IGFBP-3 could explain the difference in IGF-I between TS and control subjects. Carbohydrate metabolism in TS was comparable with control subjects. GH treatment induced insulin resistance, with increments in fasting glucose andinsulin, as well as 24-hour insulin. Circulating levels of lipid and gluconeogenic substrates were comparable in TS and control subjects and unchanged in response to treatment. Bone markers increased in response to GH. Total FM was increased in girls with TS, accounted for by an increased FM in the arms and trunk, whereas LBM was decreased. Especially LBM in the legs was decreased. Overall, bone mineral content was diminished. Treatment with GH reduced FM in TS, especially in the arms and legs, and likewise increased total LBM, primarily in the trunk.

Conclusion. This study documented evidence of impaired GH secretion and action, disproportionate body composition, but a normal carbohydrate metabolism in girls with TS. Short-term GH administration was associated with favorable changes in body composition but also with relative impairment of glucose tolerance and insulin sensitivity. We recommend that glucose metabolism be monitored carefully during long-term GH treatment in these patients.

Key Words: growth hormone treatment • glucose metabolism • insulin sensitivity • DXA scan • body composition • IGF-I • body mass index

Abbreviations: TS, Turner syndrome • GH, growth hormone • BMI, body mass index • OGTT, oral glucose tolerance test • IGF, insulin-like growth factor • IGFBP, insulin-like growth factor binding protein • FFA, free fatty acid • DXA, dual-energy x-ray absorptiometry • BMC, bone mineral content • LBM, lean body mass • FM, fat mass • HOMA, Homeostasis Model Assessment • ISIcomp, composite whole-body insulin sensitivity index • CV, coefficient of variation • RIA, radioimmunoassay • PTH, parathyroid hormone • FSH, follicle-stimulating hormone • LH, luteinizing hormone • AUC, area under the curve • BMD, bone mineral density


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
METHODS
 RESULTS
 DISCUSSION
 CONCLUSION
 REFERENCES
 
Turner syndrome (TS) is an approved indication for growth hormone (GH) treatment in many countries. Numerous studies have documented the growth-promoting effect of GH treatment in these patients, and final height can be significantly increased and perhaps even normalized with GH.1,2 Many safety aspects of GH therapy, however, have never been studied in detail. Thus, data from controlled studies on the effects on body composition, substrate metabolism, and glucose homeostasis during GH therapy are lacking. We therefore conducted a double-blind, placebo-controlled, crossover study in TS on the effect of GH on insulin sensitivity, glucose tolerance, bone turnover, and body composition.


   METHODS
TOP
 ABSTRACT
 INTRODUCTION
 METHODS
RESULTS
 DISCUSSION
 CONCLUSION
 REFERENCES
 
Patients
Twelve girls who had TS verified by chromosomal karyotyping and were aged 9.5 to 14.8 years (median: 12.9 years) were studied. None of the participants had previously received estrogen. Four of the girls were spontaneously menstruating. Eight had the karyotype 45,X; 2 had 45,X/46,XX; 1 had 46,X,i(Xq); and 1 had 45,X/46,X,i(Xq)/47,X, i(Xq), i(Xq). All subjects were staged according to Tanner. Mammary stages were as follows: stage 1, n = 7; stage 2, n = 2; stage 4, n = 3. Pubic hair stages were as follows: stage 1, n = 6; stage 2, n = 2; stage 3, n = 2; stage 4, n = 2. At least 6 months (median [range]: 34 [7–68] months) before inclusion in the study, all girls with TS received GH (0.1 IU/kg/d). There was no significant correlation between the length of GH treatment before inclusion and any of the studied parameters (results not shown). During the study, subjects received GH (Norditropin, Novo Nordisk, Bagsvaerd, Denmark) 0.1 IU/kg/d subcutaneously at bedtime, or placebo. The average daily dose was 3.5 ± 0.9 IU GH during the study period. An age-matched (range: 10.3–16.0 years; median: 12.1 years) control group (n = 16) was studied once. Mammary stages were as follows: stage 1, n = 4; stage 2, n = 2; stage 3, n = 2; stage 4, n = 6; stage 5, n = 2. Pubic hair stages were as follows: stage 1, n = 6; stage 2, n = 1; stage 4, n = 7; stage 5, n = 2.

All subjects and parents received oral and written information concerning the study before giving written informed consent. The protocol was approved by the local Scientific Ethics Committee and the Danish Board of Health.

Design
A randomized, placebo-controlled, crossover study with 2-month treatment periods each completed by a 24-hour blood-sampling period was conducted. Patients were treated with either GH or placebo. There was no washout period between the 2 study periods. The control girls were studied once.

Procedure
At the end of each 2-month period, participants were studied. Body weight was measured to the nearest 0.1 kg on an electronic scale, and body height was measured to the nearest 0.1 cm, with the subjects in underwear and barefooted. Body mass index (BMI) was calculated as weight (kg) divided by height (m) squared. Peripheral blood was sampled by an in-dwelling catheter for 24 hours starting at 5:00 PM. GH and placebo were administered at 8:00 PM. Blood was drawn, and serum was immediately separated at 4°C and stored at -20°C in multiple vials for later analysis. An oral glucose tolerance test (OGTT) according to the World Health Organization standard (1.75 g/kg glucose; maximum 75 g) was performed at 8:00 AM to 10:00 AM on the following day. During the 24-hour study period, study serum GH and insulin were measured every 60 minutes; venous blood glucose was sampled every 120 minutes; plasma lactate, alanine, glycerol, and 3-OH-butyrate were sampled every 60 minutes from 11:00 PM and onward until 11:00 AM; and serum insulin-like growth factor-I (IGF-I), IGF binding protein (IGFBP)-3, and IGFBP-1 were sampled at 0, 12, and 24 hours. Preliminary analysis showed no change in IGF and related parameters during the study period, and average values are given. During the OGTT, blood samples were drawn at 0, 15, 30, 45, 60, 75, 90, 105, and 120 minutes, and blood glucose, serum insulin, glucagon, free fatty acids (FFAs), lactate, alanine, glycerol, and 3-OH-butyrate were determined. Blood pressure was measured at each visit. Body composition was measured by whole-body dual-energy x-ray absorptiometry (DXA) with a Hologic QDR 2000/w scanner (Hologic Inc, Waltham, MA). Day-to-day variation for bone mineral content (BMC), lean body mass (LBM), and fat mass (FM) was 1% to 2%.3 Long-term stability was high, with changes of <0.2% per year.4 Biochemical markers of bone metabolism was measured in the fasting state (only in TS).

Insulin Sensitivity
Insulin sensitivity was calculated using the Homeostasis Model Assessment (HOMA) index5 and the composite whole-body insulin sensitivity index during the OGTT (ISIcomp).6 The HOMA index, which is based on simultaneous sampled fasting values of insulin and glucose, has previously been shown to correlate well with the euglycemic-hyperinsulinemic clamp in the assessment of insulin sensitivity in both normal and diabetic subjects5 and may be thought of as primarily illustrating hepatic insulin sensitivity.6 The HOMA index (R) was calculated as follows: R = fasting insulin/22.5 x e-ln fasting glucose.

The ISIcomp is a composite measure of whole-body insulin sensitivity that includes both components of hepatic and peripheral tissues and utilizes both fasting and stimulated (during an OGTT) values of glucose and insulin and is calculated as follows: ISIcomp = 10.000/{surd}(FPG x FSI) x (Mean OGTT glucose concentration x mean OGTT insulin concentration), where FPG and FSI denote fasting plasma glucose and fasting serum insulin, respectively. This measure has recently been validated in subjects with normal, impaired, and diabetic glucose tolerance against the euglycemic-hyperinsulinemic clamp, as the gold standard, and has been found to be superior to alternative measures of insulin sensitivity.6

Assays
Serum GH was measured with a double monoclonal immunofluorometric assay (DELFIA, Wallac, Finland). The interassay coefficient of variation (CV) was 1.7 and 2.4%, the intra-assay CV was 1.9 and 3.0% for samples with GH concentrations of 12.08 and 0.27 µg/L, and the detection limit was 0.01 µg/L. Serum IGF-I was measured by an in-house noncompetitive time-resolved immunofluorometric assay,7 serum insulin and plasma glucagon were measured by radioimmunoassay (RIA),8 serum IGFBP-3 was measured by RIA (Diagnostic Systems Laboratories Inc, Webster, TX), and serum IGFBP-I was measured by enzyme-linked immunosorbent assay (Medix Biochemica, Kainiainen, Finland). Blood samples for glucose determination were stored in sodium fluoride and frozen for later analysis, which was performed in duplicate by the glucose oxidase method. Serum FFA was determined by a colorimetric method with the use of a commercial kit (Wako Chemicals, Neuss, Germany). Blood samples were deproteinized with perchloric acid for determination of 3-hydroxy-butyrate, glycerol, alanine, and lactate by an automated fluorometric method.9 Serum osteocalcin (bone {gamma}-carboxyglutamic acid-containing protein) was measured by a RIA modified from that reported by Price and Nishimoto,10 using rabbit antiserum against bovine osteocalcin. Intact purified bovine osteocalcin, verified by amino acid analysis, was provided by Dr J. Poser (Procter and Gamble Co, Cincinnati, OH). The antiserum showed full cross-reactivity between human and bovine osteocalcin. The intra- and interassay CVs were 5% and 10%, respectively. Total alkaline phosphatase activity in serum was measured spectrophotometrically, using p-nitrophenylphosphate as substrate according to the method recommended by the Scandinavian Committee on Enzymes.11 The interassay CV was 5%, and the intra-assay CV was 2.5%. Serum concentrations of type 1 collagen telopeptide were measured using RIA obtained from Farmos Diagnostica (Turku, Finland).12 Intra- and interassay CVs were 6.9% and 5.4%, respectively. Serum intact parathyroid hormone (PTH) was measured using a 2-site immunoradiometric method (Allegro Intact PTH IRA, Nicholas Institute, San Juan Capistrano, CA). Intra- and interassay CVs were 4.1% and 10.0%, respectively. Serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were measured by time-resolved immunofluorometric assay (DELFIA, Wallac, Turku, Finland), with detection limits of 0.06 and 0.05 U/L, respectively. Intra- and interassay CVs both were below 8% in the FSH and LH assays. All samples from an individual patient were analyzed in the same assay.

Statistics
All statistics were performed in SPSS Windows version 10.0. Groups were compared using Student 2-tailed paired t test, independent t test, Mann-Whitney U test, or Wilcoxon test, as appropriate. All data were tested for period as well as carryover effects, which did not affect the level of significance. Repeated measures analysis of variance (general linear model) was used to test for differences between treatment modalities in the group of TS patients with time. The area under the curve (AUC) was calculated using the trapezoid rule. Pearson correlation was used to examine relations between serum IGF-I and GH and putative predicting variables (age, LBM, BMC, serum IGFBP-3, Tanner stage (mammary), and RHOMA). Having identified different variables as independent predictors of IGF-I, we used multiple backward stepwise linear regression to examine the principal determinants of IGF-I. Results are expressed as mean ± standard deviation. Statistical significance was assumed for P <5%.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS
DISCUSSION
 CONCLUSION
 REFERENCES
 
Markers of Ovarian Function
FSH was elevated in TS in comparison with control subjects (median [range]: 16.6 U/L [0.32–144 U/L] vs 3.7 U/L [1.1–8.9 U/L]; P = .05), whereas LH was comparable between groups (3.5 U/L [0.05–27.6 U/L] vs 2.1 U/L [0.05–25.6 U/L]; P = .4). FSH and LH were unchanged by treatment with placebo or GH in TS (data not shown).

Body Composition
There was no difference in age (TS vs control: 12.4 ± 1.9 vs 12.7 ± 2.1 years; P = .7), weight (36.3 ± 9.2 vs 42.7 ± 9.6 kg; P = .09), birth weight (2766 ± 490 vs 3125 ± 566 g; P = .1), or BMI (19.2 ± 2.6 vs 18.0 ± 2.1 kg/m2; P = .2) between girls with TS and control subjects, whereas height was reduced in TS (136.3 ± 9.2 vs 152.9 ± 12.3 cm; P = .001).

Total FM was increased in TS, when expressing this measure per kilogram of body weight. This was accounted for by an increased FM in the arms and trunk. Likewise, LBM was decreased in TS girls (P = .09), albeit barely reaching significance at the 5% level. Especially LBM in the legs was decreased, whereas LBM in other anatomic regions was comparable to that of control subjects. Overall, BMC was diminished, being accounted for by reductions in BMC both in the legs and in the arms (Table 1).


View this table:
[in this window]
[in a new window]
  		TABLE 1. Anthropometric Measures and Body Composition as Assessed by DXA

 
Treatment with GH reduced total FM in TS, especially in the arms and legs, and likewise increased total LBM, primarily in the trunk. No significant changes were seen in BMC during treatment (P = .1).

GH Secretion and Circulating Levels of IGF-I and IGFBP-3 in Untreated TS Versus Control Subjects
In the placebo situation, 24-hour integrated serum GH was significantly reduced in girls with TS compared with control subjects, as were serum IGF-I and the IGF-I/IGFBP-3 ratio, whereas serum IGFBP-1 and IGFBP-3 levels were comparable in the 2 groups (Table 2). There was a strong positive linear correlation between 24-hour integrated serum GH and LBM (r = 0.703, P = .01) and Tanner stage (mammary; r = 0.630, P = .028) in placebo-treated girls with TS but not in control subjects. There was no significant correlation between FM and 24-hour integrated serum GH in TS or control subjects. Controlling for differences in LBM and Tanner stage in a multiple regression analysis, however, did not explain the observed difference in 24-hour integrated serum GH. Serum IGF-I correlated positively with BMC (TS: r = 0.818, P = .001; control: r = 0.571, P = .021), LBM (TS: r = 0.796, P = .002; control: r = 0.618, P = .011), age (TS: r = 0.730, P = .007; control: r = 0.637, P = .008), serum IGFBP-3 (TS: r = 0.757, P = .004; control: r = 0.805, P < .0005), and Tanner stage (mammary) (TS: r = 0.846, P = .001; control: r = 0.697, P = .003) in both TS and control subjects. In TS, serum IGF-I also showed significant correlation with BMI (r = 0.747, P = .007), whereas in control subjects, serum IGF-I correlated significantly with total FM (r = 0.520, P = .039) and RHOMA (r = 0.568, P = .022). There were no correlations between 24-hour integrated serum GH and either serum IGF-I or age. The variables that showed significant bivariate correlations with serum IGF-I in TS and control subjects including status (ie, being a TS or a control subject) were entered into a stepwise multiple regression model, with serum IGF-I as the dependent variable. Tanner stage (mammary; P < .0005), BMI (P = .021), FM (P = .074), RHOMA (P = .001), and serum IGFBP-3 (P = .001) all were significant explanatory variables, whereas status was not.


View this table:
[in this window]
[in a new window]
  		TABLE 2. Mean ± SD levels of GH, IGF-I, IGFBP-1, IGFBP-3, Glucose, Insulin, and Measures From the OGTT in TS and Control Subjects

 
GH Secretion and Circulating Levels of IGF-I and IGFBP-3: Effect of GH Treatment
All measures of the GH-IGF axis increased significantly with treatment (serum GH by 282%; serum IGF-I by 212%; serum IGFBP-3 by 138%; IGF-I/IGFBP-3 ratio by 159%), except for serum IGFBP-1, which decreased significantly by 64% (Table 2).

OGTT and Insulin Sensitivity, and Circulating Lipid and Gluconeogenic Intermediates in Untreated TS Versus Control Subjects
Fasting blood glucose, serum insulin, and glucagon were comparable in TS and control subjects (Table 2). Likewise, measures from the OGTT (glucose: 768 ± 106 vs 721 ± 90 mmol/L/120 min, P = .2; insulin: 7916 ± 3392 vs 9183 ± 4876 mU/L/120 min, P = .4) and the 2 indices of insulin sensitivity were comparable in the 2 groups, whereas AUCglucagon during the OGTT was reduced in girls with TS in comparison with control subjects (449 ± 96 vs 629 ± 214 ng/L/120 min, P = .01; Fig 1). There was no significant correlation between birth weight and the different measures of insulin sensitivity (results not shown).



View larger version (20K):
[in this window]
[in a new window]
  		Fig 1. A, Plasma glucose during the OGTT in 12 girls with TS after 2 months of treatment with placebo (open circles with solid line) or GH (0.1 IU/kg/d; solid circles with solid line) in randomized order and in 16 control girls (open squares with dotted line). B, Serum insulin during the OGTT in 12 girls with TS after 2 months of treatment with placebo (open circles with solid line) or GH (0.1 IU/kg/d; solid circles with solid line) in randomized order and in 16 control girls (open squares with dotted line). C, Serum glucagon during the OGTT in 12 girls with TS after 2 months of treatment with placebo (open circles with solid line) or GH (0.1 IU/kg/d; solid circles with solid line) in randomized order and in 16 control girls (open squares with dotted line). Significance level is given in the figure throughout.

 
The circulating levels of lipid and gluconeogenic substrates overnight and during the OGTT all were comparable between girls with TS and control subjects (Table 3).


View this table:
[in this window]
[in a new window]
  		TABLE 3. Circulating Lipid and Gluconeogenic Intermediates

 
OGTT and Insulin Sensitivity, and Circulating Lipid and Gluconeogenic Intermediates: Effect of GH Treatment
In response to treatment with GH, significant increments were recorded in almost all measures (Table 2). Fasting blood glucose and serum insulin increased, as did AUCglucose (TSplacebo vs TSGH: 768 ± 106 vs 863 ± 73 mmol/L/120 min, P = .027) and AUCinsulin (7916 ± 3392 vs 13424 ± 4709 mU/L/120 min, P < .0005) during the OGTT (Fig 1), and AUCinsulin during the entire 24-hour study period (Fig 2), whereas AUCglucose during the same period was unchanged. Insulin resistance increased, as evidenced from reduced ISIcomp and increased RHOMA. AUCglucagon (449 ± 96 vs 505 ± 178 ng/L/120 min, P = .2) was unchanged. There was no significant difference between placebo and GH treatment in the circulating levels of gluconeogenic and lipid substrates, overnight or during the OGTT (Table 3).



View larger version (17K):
[in this window]
[in a new window]
  		Fig 2. Twenty-four-hour insulin levels in 12 girls with TS after 2 months of treatment with placebo (open circles with solid line) or GH (0.1 IU/kg/d; solid circles with solid line) in randomized order and in 16 control girls (open squares with dotted line). Significance level is given in the figure.

 
Biochemical Markers of Bone Formation and Resorption
The level of serum type 1 collagen telopeptide (placebo vs GH: 11.4 ± 1.8 vs 14.9 ± 2.2 2g/L, P = .008) and osteocalcin (52.8 ± 21.4 vs 73.1 ± 18.7 7g/L, P = .003) increased in response to treatment, as did serum alkaline phosphatase (375 ± 124 vs 434 ± 169 U/L, P = .06), albeit not significantly. Serum PTH was unchanged during GH treatment (36.8 ± 9.4 vs 33.4 ± 6.2 ng/L, P = .3).


   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS
 DISCUSSION
CONCLUSION
 REFERENCES
 
The current study, which to our knowledge is the first randomized trial of GH and placebo in TS studying metabolic effects, demonstrates distinct effects of GH in TS but also differences between TS and control subjects. The rationale for GH treatment in TS is poor growth rather than impaired endogenous GH secretion. Previous studies have, however, reported both normal13–15 and diminished16,17 spontaneous and stimulated GH secretion in TS. The bioactivity of circulating GH in TS has been reported to be reduced,18 and different patterns of GH isoforms have been found by some19 but not by others.20 The normal increase in GH secretion during puberty is absent in girls with TS but may be partially restored by replacement of female sex hormones.21,22 In girls with TS, levels of serum total (extractable) IGF-I levels have been found to be lower than21 or comparable to age-matched control subjects.22 Untreated adult patients with TS have normal serum levels of total IGF-I and IGFBP-3 but lower levels of free IGF-I,23 and the secretion of GH shows increased irregularity (disorderliness) when 24-hour sampled series are assessed.24 Thus, although the general belief has been that the GH-IGF-I axis is normal or near normal in TS, these recent results suggest a partially disturbed GH-IGF-IGFBP axis. In accordance with that, we found reductions in the 24- hour integrated serum GH, as well as in the serum levels of IGF-I and the IGF-I/IGFBP-3 ratio, whereas serum IGFBP-1 was increased. As expected, GH treatment increased all 3 components of the GH-IGF-I-IGFBP-3 axis significantly while decreasing IGFBP-1. It is interesting that 24-hour GH secretion was strongly correlated to LBM (but not FM) in TS but not in control subjects. Although there were differences in LBM between the 2 study groups, these differences did not explain the lower 24-hour integrated serum GH in TS, contrary to the situation in adult TS, where differences in LBM and physical fitness could explain the lower 24-hour GH secretion.25 Even more interesting, the significant differences in the level of total serum IGF-I between placebo-treated girls with TS and control subjects could be explained by the differences in Tanner stage, BMI, total FM, RHOMA, and serum IGFBP-3. This result should not be interpreted as a cause and effect relationship but rather as an indication that these variables are interrelated. Although the participants with TS and the control subjects were age matched, they were invariably not in the same pubertal stage. It is widely known that increase in Tanner stage and age during puberty is associated with increased levels of serum IGF-I.26 Furthermore, serum IGF-I showed a strong positive correlation with BMC and LBM. In a recent study of bone morphology in adults with TS, we found strong correlations between the area of the hip and the forearm and serum IGF-I, and likewise we found serum IGF-I to be a contributory variable in explaining the volumetric area of the lumbar vertebrae.27 Serum IGF-I has also been shown to be positively correlated with changes in bone mineral density (BMD) in the femoral neck and the ultradistal forearm in normal women,28 and recent studies of girls who have TS and were receiving GH showed that these girls have normal BMD through puberty, despite apparently rather late introduction to estrogens.29–32 This suggests that supraphysiologic (acromegalic) levels of serum GH (and thus serum IGF-I) are necessary to reach normal BMD (and possibly skeletal size) in girls with TS, and thus a close link between the IGF axis and BMC seems to exist.

In the present study, biochemical markers of bone formation and resorption increased significantly in response to GH treatment, corroborating numerous other studies in normal subjects33,34 and in patients with osteoporosis35 and GH deficiency.36 Although no histomorphometric data on bone biopsies have been published in TS, data from GH-deficient adults37 demonstrate that GH increases bone turnover at the tissue level and supports the use of biochemical markers in the present setting. The increased turnover, in theory, should increase the remodeling space (ie, the amount of bone resorbed and yet not reformed during the process of remodeling at any given time) and most likely explains the decrease in BMC or BMD seen in our relatively short-term study.

GH treatment did not influence circulating markers of gluconeogenesis or lipolysis. GH has well-known effects on lipolysis,38,39 and although AUCs of glycerol, 3-hydroxy-butyrate, and FFA all increased, the present absence of any statistically discernible increase in lipolytic parameters might be attributable to a type 2 error. Alternatively, it is plausible that the GH-induced increase in lipid intermediates were transient and had subsided at the end of the study period.

During placebo treatment, most measures relating to carbohydrate metabolism were comparable with of that of the control group. The 2 groups were well-matched with BMI and age, although differences were found when results from the DXA scans were studied. This is in contrast with previous reports of insulin resistance in girls with TS when using the hyperinsulinemic-euglycemic clamp.40,41 There are several possible explanations for the discordant findings. First, in the study of Caprio et al,40 the group of girls with TS and the control subjects were not well-matched for BMI (ie, the group of girls with TS had significantly higher BMI, and fasting glucose and insulin levels were higher in TS). Second, in the study of Stoppoloni et al,41 fasting insulin levels were higher in girls with TS. Third, we applied an OGTT rather than the euglycemic-hyperinsulinemic clamp, which is considered the gold standard for determining insulin sensitivity. Of note, however, using an OGTT with ISIcomp analysis in adult TS, we recently showed a significant difference in insulin sensitivity between 2 very well-matched groups of TS and control subjects.42 In this same study, we showed impaired glucose tolerance and enlarged type 2a muscle fibers in TS,42 a feature also found in postmenopausal women with impaired glucose tolerance.43 Finally, the control group may have been relatively insulin resistant, as a result of the advent of puberty. The AUC of glucagon was diminished during the OGTT in the placebo-treated TS group. Along with the decreased 24-hour integrated serum GH, the results point toward a decrease in the counterregulatory hormones in TS. Reduced secretion of gastric inhibitory polypeptide has also been suggested to explain part of the increased frequency of impaired glucose tolerance in TS.44,45 Treatment with GH induced the expected findings with hyperinsulinemia and insulin resistance also found in a number of previous uncontrolled and long-term studies.46–48 However, probably because of the design of the present study, we were also able to show that treatment with GH induces an elevation of fasting glucose, AUCOGTT glucose, and the 24-hour secretion of insulin. Birth weight, although not significantly reduced among TS in the current study, perhaps as a result of a type 2 error, has previously been found to be reduced in a large study.49 Low birth weight may be a contributing factor in the high risk of developing facets of the metabolic syndrome among adult TS, as seen in the general population,50 as well as the advent of premature adrenarche,51 although the latter has not been described in TS. We did not assess adrenal function in the present study, but a high frequency of heterozygosity for 21-hydroxylase deficiency has been found in Italian TS,52 and GH treatment has been shown to increase responsiveness of adrenal steroidogenesis (the {Delta}5 pathway) to ACTH testing.53 At present, it is not possible to state clearly the effects on insulin sensitivity and body composition that these changes may have.

Although BMI was comparable in the 2 study groups, DXA scanning showed distinct differences in body composition when total body weight was controlled for. Not only did TS have a higher percentage of body fat and less bone mineral, but they also tended to have a lower LBM (P = .09). Detailed assessment of individual regions revealed additional differences, with fat being deposited excessively primarily in the arms and trunk in TS, whereas BMC and LBM were especially reduced in the legs. This suggests that body compositional disproportionality, in line with previously documented anthropometric54 and bone disproportionality,27 is a feature of the syndrome. The genetic or developmental background for these differences is not entirely clear. Recently, a study of adults with TS examined by DXA scans reported the lumbar projected bone area to be normal, whereas the proximal femur area was increased (11%) and the distal forearm area was severely reduced (37%) compared with healthy control subjects.27 Moreover, these abnormalities were suggested to be caused by haploinsufficiency of the SHOX gene. Short-term GH treatment caused a partial normalization of body composition, although distinct abnormalities were still evident. Total FM decreased, whereas LBM increased during 2 months of GH treatment. Especially FM of the arms and legs was decreased, whereas LBM on the trunk increased. However, it seemed that truncal FM remained excessive in comparison with the control group, although no formal statistical evaluation was performed. Likewise, LBM of the legs also seemed to be distinctly reduced. The changes in body composition might be coupled to the reduced physical fitness seen in adults with TS.25 Longer term evaluations of GH treatment in TS would be of great interest, to establish whether a normalization of LBM and FM is possible.


   CONCLUSION
TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS
 DISCUSSION
 CONCLUSION
REFERENCES
 
This study documented evidence of impaired GH secretion and action in girls with TS. Short-term GH administration was associated with favorable changes in body composition but also with relative impairment of glucose tolerance and insulin sensitivity. We recommend that glucose metabolism be monitored carefully during long-term GH treatment in these patients.


   ACKNOWLEDGMENTS
 
This study was supported by Danish Health Research Council grant 9600822 (Aarhus University-Novo Nordisk Center for Research in Growth and Regeneration).

Dr Gravholt is the recipient of honoraria from Pharmacia and Novo Nordisk. Dr Christiansen is the recipient of research grants from Eli Lilly, Novo Nordisk, and Roche and has received honoraria from the same companies.

We thank Ole Andersen, MD, for enthusiastic encouragement and kind referral of patients; Joan Hansen, Kirsten Nyborg, Inga Bisgaard, Else Rasmussen, and Donna Arbuckle Lund for expert technical help; ÅSE Ejlertsen for assistance with the recruitment and service of the girls with TS; and Birthe Gosvig for secretarial assistance.


   FOOTNOTES
 
Received for publication Oct 1, 2001; Accepted Apr 10, 2002.

Reprint requests to (C.H.G.) Medical Department M (Endocrinology and Diabetes), Århus Kommunehospital, DK-8000 Aarhus C, Denmark. E-mail: ch.gravholt{at}dadlnet.dk

Drs Gravholt and Naeraa contributed equally to this work.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS
 DISCUSSION
 CONCLUSION
 REFERENCES
 

  1. Rosenfeld RG, Attie KM, Frane J, et al. Growth hormone therapy of Turner’s syndrome: beneficial effect on adult height. J Pediatr.1998; 132 :319 –324[CrossRef][ISI][Medline]
  2. Sas TC, Muinck Keizer-Schrama SM, Stijnen T, et al. Normalization of height in girls with Turner syndrome after long-term growth hormone treatment: results of a randomized dose-response trial. J Clin Endocrinol Metab.1999; 84 :4607 –4612[Abstract/Free Full Text]
  3. Jensen MB, Hermann AP, Hessov IB, Mosekilde L. Components of variance when assessing the reproducibility of body composition measurements using bio-impedance and the Hologic QDR-2000 DXA scanner. Clin Nutr.1997; 16 :61 –65
  4. Abrahamsen B, Gram J, Hansen TB, Beck NH. Cross calibration of QDR-2000 and QDR-1000 dual-energy X-ray densitometers for bone mineral and soft-tissue measurements. Bone.1995; 16 :385 –390[Medline]
  5. Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia.1985; 28 :412 –419[CrossRef][ISI][Medline]
  6. Matsuda M, DeFronzo RA. Insulin sensitivity indices obtained from oral glucose tolerance testing: comparison with the euglycemic insulin clamp. Diabetes Care.1999; 22 :1462 –1470[Abstract/Free Full Text]
  7. Frystyk J, Dinesen B, Orskov H. Non-competitive time-resolved immunofluorometric assays for determination of human insulin-like growth factor I and II. Growth Regul.1995; 5 :169 –176[ISI][Medline]
  8. Orskov H, Thomsen HG, Yde H. Wick chromatography for rapid and reliable immunoassay of insulin, glucagon and growth hormone. Nature.1968; 219 :193 –195[Medline]
  9. Lloyd B, Burrin J, Smythe P, Alberti KG. Enzymic fluorometric continuous-flow assays for blood glucose, lactate, pyruvate, alanine, glycerol, and 3-hydroxybutyrate. Clin Chem.1978; 24 :1724 –1729[Abstract/Free Full Text]
  10. Price PA, Nishimoto SK. Radioimmunoassay for the vitamin K-dependent protein of bone and its discovery in plasma. Proc Natl Acad Sci U S A.1980; 77 :2234 –2238[Abstract/Free Full Text]
  11. Recommended methods for the determination of four enzymes in blood. Scand J Clin Lab Invest.1974; 33 :291 –306[ISI][Medline]
  12. Risteli J, Elomaa I, Niemi S, Novamo A, Risteli L. Radioimmunoassay for the pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen: a new serum marker of bone collagen degradation. Clin Chem.1993; 39 :635 –640[Abstract/Free Full Text]
  13. Ranke MB, Blum WF, Haug F, et al. Growth hormone, somatomedin levels and growth regulation in Turner’s syndrome. Acta Endocrinol.1987; 116 :305 –313
  14. Saenger P, Schwartz E, Wiedemann E, Levine LS, Tsai M, New MI. The interaction of growth hormone, somatomedin and oestrogen in patients with Turner’s syndrome. Acta Endocrinol.1976; 81 :9 –18
  15. Wit JM, Massarano AA, Kamp GA, et al. Growth hormone secretion in patients with Turner’s syndrome as determined by time series analysis. Acta Endocrinol.1992; 127 :7 –12
  16. Massarano AA, Brook CG, Hindmarsh PC, et al. Growth hormone secretion in Turner’s syndrome and influence of oxandrolone and ethinyl oestradiol. Arch Dis Child.1989; 64 :587 –592[Abstract]
  17. Reiter JC, Craen M, Van Vliet G. Decreased growth hormone response to growth hormone-releasing hormone in Turner’s syndrome: relation to body weight and adiposity. Acta Endocrinol.1991; 125 :38 –42
  18. Foster CM, Borondy M, Markovs ME, Hopwood NJ, Kletter GB, Beitins IZ. Growth hormone bioactivity in girls with Turner’s syndrome: correlation with insulin-like growth factor I. Pediatr Res.1994; 35 :218 –222[ISI][Medline]
  19. Blethen SL, Albertsson Wikland K, Faklis EJ, Chasalow FI. Circulating growth hormone isoforms in girls with Turner’s syndrome. J Clin Endocrinol Metab.1994; 78 :1439 –1443[Abstract]
  20. Ishikawa M, Yokoya S, Tachibana K, et al. Serum levels of 20-kilodalton human growth hormone (GH) are parallel those of 22-kilodalton human GH in normal and short children. J Clin Endocrinol Metab.1999; 84 :98 –104[Abstract/Free Full Text]
  21. Ross JL, Long LM, Loriaux DL, Cutler GBJ. Growth hormone secretory dynamics in Turner syndrome. J Pediatr.1985; 106 :202 –206[CrossRef][ISI][Medline]
  22. Zadik Z, Landau H, Chen M, Altman Y, Lieberman E. Assessment of growth hormone (GH) axis in Turner’s syndrome using 24-hour integrated concentrations of GH, insulin-like growth factor-I, plasma GH-binding activity, GH binding to IM9 cells, and GH response to pharmacological stimulation. J Clin Endocrinol Metab.1992; 75 :412 –416[Abstract]
  23. Gravholt CH, Frystyk J, Flyvbjerg A, Orskov H, Christiansen JS. Reduced free IGF-I and increased IGFBP-3 proteolysis in Turner syndrome: modulation by female sex steroids. Am J Physiol.280 :E308 –E314,2001[Abstract/Free Full Text]
  24. Gravholt CH, Veldhuis JD, Christiansen JS. Increased disorderliness and decreased mass and daily rate of endogenous growth hormone secretion in adult Turner syndrome: the impact of body composition, maximal oxygen uptake and treatment with sex hormones. Growth Horm IGF Res.1998; 8 :289 –298[CrossRef][ISI][Medline]
  25. Gravholt CH, Naeraa RW, Fisker S, Christiansen JS. Body composition and physical fitness are major determinants of the growth hormone-IGF axis aberrations in adult Turner syndrome, with important modulations by treatment with 17-beta-estradiol. J Clin Endocrinol Metab.1997; 82 :2570 –2577[Abstract/Free Full Text]
  26. Juul A, Bang P, Hertel NT, et al. Serum insulin-like growth factor-I in 1030 healthy children, adolescents, and adults: relation to age, sex, stage of puberty, testicular size, and body mass index. J Clin Endocrinol Metab.1994; 78 :744 –752[Abstract]
  27. Gravholt CH, Lauridsen AL, Brixen K, Mosekilde L, Heickendorff L, Christiansen JS. Marked disproportionality in bone size and mineral, and distinct abnormalities in bone markers and calcitropic hormones in adult Turner syndrome. A cross-sectional study. J Clin Endocrinol Metab.2002; 87 :2798 –2808[Abstract/Free Full Text]
  28. Vestergaard P, Hermann AP, Orskov H, Mosekilde L. Effect of sex hormone replacement on the insulin-like growth factor system and bone mineral: a cross-sectional and longitudinal study in 595 perimenopausal women participating in the Danish Osteoporosis Prevention Study. J Clin Endocrinol Metab.1999; 84 :2286 –2290[Abstract/Free Full Text]
  29. Neely EK, Marcus R, Rosenfeld RG, Bachrach LK. Turner syndrome adolescents receiving growth hormone are not osteopenic. J Clin Endocrinol Metab.1993; 76 :861 –866[Abstract]
  30. Lanes R, Gunczler P, Paoli M, Weisinger JR. Bone mineral density of prepubertal age girls with Turner’s syndrome while on growth hormone therapy. Horm Res.1995; 44 :168 –171[ISI][Medline]
  31. Bertelloni S, Cinquanta L, Baroncelli GI, Simi P, Rossi S, Saggese G. Volumetric bone mineral density in young women with Turner’s syndrome treated with estrogens or estrogens plus growth hormone. Horm Res.2000; 53 :72 –76[CrossRef][ISI][Medline]
  32. Sas TC, Muinck Keizer-Schrama SM, Stijnen T, et al. A longitudinal study on bone mineral density until adulthood in girls with Turner’s syndrome participating in a growth hormone injection frequency-response trial. Clin Endocrinol (Oxf).2000; 52 :531 –536[CrossRef][Medline]
  33. Brixen K, Nielsen HK, Mosekilde L, Flyvbjerg A. A short course of recombinant human growth hormone treatment stimulates osteoblasts and activates bone remodeling in normal human volunteers. J Bone Miner Res.1990; 5 :609 –618[ISI][Medline]
  34. Marcus R, Butterfield G, Holloway L, et al. Effects of short term administration of recombinant human growth hormone to elderly people. J Clin Endocrinol Metab.1990; 70 :519 –527[Abstract]
  35. Brixen K, Kassem M, Nielsen HK, Loft AG, Flyvbjerg A, Mosekilde L. Short-term treatment with growth hormone stimulates osteoblastic and osteoclastic activity in osteopenic postmenopausal women: a dose response study. J Bone Miner Res.1995; 10 :1865 –1874[ISI][Medline]
  36. Hansen TB, Brixen K, Vahl N, et al. Effects of 12 months of growth hormone (GH) treatment on calciotropic hormones, calcium homeostasis, and bone metabolism in adults with acquired GH deficiency: a double blind, randomized, placebo-controlled study. J Clin Endocrinol Metab.1996; 81 :3352 –3359[Abstract]
  37. Brixen K, Hansen TB, Hauge E, et al. Growth hormone treatment in adults with adult-onset growth hormone deficiency increases iliac crest trabecular bone turnover: a 1-year, double-blind, randomized, placebo-controlled study. J Bone Miner Res.2000; 15 :293 –300[CrossRef][ISI][Medline]
  38. Ikkos D, Luft R, Gemzell CA. The effect of human growth hormone in man. Lancet.1958; 1 :720 –721
  39. Raben MS, Hollenberg CH. Effect of growth hormone on plasma fatty acids. J Clin Invest.1959; 38 :484 –488
  40. Caprio S, Boulware S, Diamond M, et al. Insulin resistance: an early metabolic defect of Turner’s syndrome. J Clin Endocrinol Metab.1991; 72 :832 –836[Abstract]
  41. Stoppoloni G, Prisco F, Alfano C, Iafusco D, Marrazzo G, Paolisso G. Characteristics of insulin resistance in Turner syndrome. Diabetes Metab.1990; 16 :267 –271
  42. Gravholt CH, Nyholm B, Saltin B, Schmitz O, Christiansen JS. Muscle fiber composition and capillary density in Turner syndrome: evidence of increased muscle fiber size related to insulin resistance. Diabetes Care.2001; 24 :1668 –1673[Abstract/Free Full Text]
  43. Larsson H, Daugaard JR, Kiens B, Richter EA, Ahren B. Muscle fiber characteristics in postmenopausal women with normal or impaired glucose tolerance. Diabetes Care.1999; 22 :1330 –1338[Abstract]
  44. Heinze E, Schlickenrieder J, Holl RW, Ebert R. Reduced secretion of gastric inhibitory polypeptide in Turner patients with impaired glucose tolerance. Eur J Pediatr.1991; 150 :339 –342[CrossRef][ISI][Medline]
  45. Heinze E, Clark PMS, Hales CN, Orskov C, Ebert W, Holl RW. Reduced GIP contributes to altered insulin response following oral glucose in women with Turner syndrome. Diabetologia.1993; 36(suppl 1) :A48 –A48. Abstract 182
  46. Wilson DM, Frane JW, Sherman B, Johanson AJ, Hintz RL, Rosenfeld RG. Carbohydrate and lipid metabolism in Turner syndrome: effect of therapy with growth hormone, oxandrolone, and a combination of both. J Pediatr.1988; 112 :210 –217[CrossRef][ISI][Medline]
  47. Caprio S, Boulware SD, Press M, et al. Effect of growth hormone treatment on hyperinsulinemia associated with Turner syndrome. J Pediatr.1992; 120 :238 –243[CrossRef][ISI][Medline]
  48. Sas TC, Muinck Keizer-Schrama SM, Stijnen T, Aanstoot HJ, Drop SL. Carbohydrate metabolism during long-term growth hormone (GH) treatment and after discontinuation of GH treatment in girls with Turner syndrome participating in a randomized dose-response study. Dutch Advisory Group on Growth Hormone. J Clin Endocrinol Metab.2000; 85 :769 –775[Abstract/Free Full Text]
  49. Ranke MB, Pfluger H, Rosendahl W, et al. Turner syndrome: spontaneous growth in 150 cases and review of the literature. Eur J Pediatr.1983; 141 :81 –88[CrossRef][ISI][Medline]
  50. Phipps K, Barker DJ, Hales CN, Fall CH, Osmond C, Clark PM. Fetal growth and impaired glucose tolerance in men and women. Diabetologia.1993; 36 :225 –228[CrossRef][ISI][Medline]
  51. Ibanez L, Dimartino-Nardi J, Potau N, Saenger P. Premature adrenarche—normal variant or forerunner of adult disease? Endocr Rev.2000; 21 :671 –696[Abstract/Free Full Text]
  52. Larizza D, Cuccia M, Martinetti M, et al. Adrenocorticotrophin stimulation and HLA polymorphisms suggest a high frequency of heterozygosity for steroid 21-hydroxylase deficiency in patients with Turner’s syndrome and their families. Clin Endocrinol (Oxf).1994; 40 :39 –45[Medline]
  53. Balducci R, Toscano V, Larizza D, et al. Effects of long-term growth hormone therapy on adrenal steroidogenesis in Turner syndrome. Horm Res.1998; 49 :210 –215[CrossRef][ISI][Medline]
  54. Gravholt CH, Naeraa RW. Reference values for body proportions and body composition in adult women with Turner’s syndrome. Am J Med Genet.1997; 72 :403 –408[CrossRef][ISI][Medline]
PEDIATRICS (ISSN 1098-4275). ©2002 by the American Academy of Pediatrics



This article has been cited by other articles:


Home page
 J. Clin. Endocrinol. Metab.Home page
N. Wooten, V. K. Bakalov, S. Hill, and C. A. Bondy
Reduced Abdominal Adiposity and Improved Glucose Tolerance in Growth Hormone-Treated Girls with Turner Syndrome
J. Clin. Endocrinol. Metab., June 1, 2008; 93(6): 2109 - 2114.
[Abstract] [Full Text] [PDF]

Home page
 J. Clin. Endocrinol. Metab.Home page
M. Ari, V. K. Bakalov, S. Hill, and C. A. Bondy
The Effects of Growth Hormone Treatment on Bone Mineral Density and Body Composition in Girls with Turner Syndrome
J. Clin. Endocrinol. Metab., November 1, 2006; 91(11): 4302 - 4305.
[Abstract] [Full Text] [PDF]

Home page
 Eur J EndocrinolHome page
C. H. Gravholt, B. E. Hjerrild, L. Mosekilde, T. K. Hansen, L. M. Rasmussen, J. Frystyk, A. Flyvbjerg, and J. S. Christiansen
Body composition is distinctly altered in Turner syndrome: relations to glucose metabolism, circulating adipokines, and endothelial adhesion molecules.
Eur. J. Endocrinol., October 1, 2006; 155(4): 583 - 592.
[Abstract] [Full Text] [PDF]

Home page
 J. Clin. Endocrinol. Metab.Home page
C. A. Bondy, P. L. Van, V. K. Bakalov, and V. B. Ho
Growth Hormone Treatment and Aortic Dimensions in Turner Syndrome
J. Clin. Endocrinol. Metab., May 1, 2006; 91(5): 1785 - 1788.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow P3Rs: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when P3Rs are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow E-mail this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My File Cabinet
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via ISI Web of Science (15)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Gravholt, C. H.
Right arrow Articles by Christiansen, J. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gravholt, C. H.
Right arrow Articles by Christiansen, J. S.
Related Collections
Right arrow Endocrinology