
<ArticleTitle><prot>Leptin</prot> levels in preterm human breast milk and infant formula.</ArticleTitle>
<AbstractText>OBJECTIVE: <prot>Leptin</prot>, a hormone present in breast milk, is involved in energy regulation and metabolism. The purpose of this investigation was to determine whether <prot>leptin</prot> is present in either preterm breast milk (PBM) or preterm formula (PF). The effects of delivery methods and pasteurization on <prot>leptin</prot> levels also were evaluated. METHODS: PBM samples were obtained from 29 mothers who delivered infants at between 23 and 34 weeks' gestation. <prot>Leptin</prot> levels were measured in PBM and PF with the use of a radioimmunoassay specific for human and bovine <prot>leptin</prot>, 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 <prot>leptin</prot> levels. RESULTS: Median PBM <prot>leptin</prot> 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 <prot>leptin</prot> levels. Neither bolus nor continuous feeding practices affected <prot>leptin</prot> levels in PBM or spiked PF. However, pasteurization significantly reduced the amount of detectable <prot>leptin</prot> in PBM. CONCLUSIONS: PBM <prot>leptin</prot> levels were highly variable and similar to levels reported for term breast milk. There was no effect of postnatal age on PBM <prot>leptin</prot> concentrations. Sterilization decreased detectable <prot>leptin</prot> levels, whereas feeding practices had no adverse effect on the quantity of <prot>leptin</prot> delivered. Although no infant formula contained <prot>leptin</prot>, <prot>leptin</prot> could be added to formula and delivered through various feeding methods without loss.</AbstractText>
