PEDIATRICS Vol. 108 No. 1 July 2001, p. e15
ELECTRONIC ARTICLE:
Leptin Levels in Preterm Human Breast Milk and Infant Formula
Received Nov 2, 2000; accepted Feb 14, 2001.
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From the * Department of Neonatology, Shady Grove Adventist
Hospital, Rockville, Maryland; Objective. Leptin, a hormone present
in breast milk, is involved in energy regulation and metabolism. The
purpose of this investigation was to determine whether leptin is
present in either preterm breast milk (PBM) or preterm formula (PF).
The effects of delivery methods and pasteurization on leptin levels
also were evaluated.
Methods. PBM samples were obtained from 29 mothers who
delivered infants at between 23 and 34 weeks' gestation. Leptin levels
were measured in PBM and PF with the use of a radioimmunoassay specific for human and bovine leptin, respectively. Milk samples were
pasteurized by fast- and slow-heating methods. PBM and PF spiked with
human leptin were delivered through catheters by bolus and continuous administration to determine the effects of delivery method on recoverable leptin levels.
Results. Median PBM leptin concentration was 5.28 ng/mL
(intraquartile range: 24.79). Birth gestational age, birth weight, and
gender of the infant did not significantly influence PBM leptin levels. Neither bolus nor continuous feeding practices affected leptin levels
in PBM or spiked PF. However, pasteurization significantly reduced the
amount of detectable leptin in PBM.
Conclusions. PBM leptin levels were highly variable and
similar to levels reported for term breast milk. There was no effect of
postnatal age on PBM leptin concentrations. Sterilization decreased
detectable leptin levels, whereas feeding practices had no adverse
effect on the quantity of leptin delivered. Although no infant formula contained leptin, leptin could be added to formula and delivered through various feeding methods without loss.
Department of Medical Research,
Alfred I. duPont Hospital for Children, Wilmington, Delaware; and
§ Department of Neonatology, Christiana Care Health Services, Newark,
Delaware.




