PEDIATRICS Vol. 102 No. 2 Supplement August 1998, pp. 521-524
Received Feb 6, 1998; accepted Mar 20, 1998.
,
From the Departments of * Pediatrics,
Biochemistry and
Microbiology, and
Pharmacology and Therapeutics, University of South
Florida College of Medicine, Tampa, Florida; and the § Department of
Biostatistics and Medical Information, Genentech Inc, South San
Francisco, California.
We analyzed 12-hour serial sampling of growth hormone (GH) levels in two cohorts of short children: 96 children referred to a university endocrine clinic or studied on a research protocol and 825 children in the National Cooperative Growth Study of children treated with exogenous GH.
The mean 12-hour GH levels correlated with growth velocity in 60 children with normal height and growth velocity in the university study, and this correlation was stronger in the boys. The testosterone levels also correlated with growth velocity and mean 12-hour GH levels in the boys. The mean 12-hour GH levels were lower in a group of 36 children with idiopathic short stature than in the control subjects, as were the peak GH levels within 1 hour after the onset of sleep and the insulin-like growth factor I levels.
In the National Cooperative Growth Study cohort, pooled 12-hour GH levels were lower in the group with idiopathic GH deficiency (n = 300) than in the group with idiopathic short stature (n = 525), but the difference was not significant. The duration of GH treatment was the most significant predictor of change in the height SD score in both groups. Indices of spontaneous secretion of GH were not predictive of the response to GH treatment, nor were the results of provocative GH testing, the responses to GH treatment being similar in both groups over time.
We conclude that the results of GH testing must be interpreted for each patient and that several testing modalities may be helpful in finding GH insufficiency that originates at various levels of the somatotropic axis.
Key words: growth hormone, growth hormone neurosecretory dysfunction, insulin-like growth factor I, NCGS (National Cooperative Growth Study).