文本框: DYNAMIC CHANGES IN SERUM LEPTIN CONCENTRATIONS DURING PERINATAL PERIODS CHEN R, BEN XM Nanjing Children's Hospital, Nanjing, China Objective: There are substantial alterations in fuel homeostasis immediately after birth. Leptin is a putative regulator of energy metabolism. Consequently, the aim of this study was to examine whether there are changes in circulating leptin concentrations during the early postnatal period and its potential effects. Methods: Blood was taken from 65 women just before delivery, and the umbilical cord mixed blood samples were taken at delivery. Venous blood samples was obtained from 73 healthy newborn infants within 7days after birth and neonatal anthropometric measurements were recorded at the same time. Serum leptin was measured by radio-immunoassay and multiple regression analysis was applied to determine which variables remained independently associated with leptin. Results: The leptin concentration (X±SD)in maternal serum was 19.93±7.21 ng/ml and in cord blood was 10.50±3.45 ng/mL. Cord leptin levels correlated with placental weight and neonatal skinfold thickness but not with maternal leptin levels. Neonatal plasma leptin concentration was 2.39±1.15 ng/mL that was significantly less than that in cord blood (p<0.01). Neonatal plasma leptin levels correlated with neonatal food intake but not with skinfold thickness. Conclusions: Relatively big serum leptin concentration gradient between maternal, umbilical and neonatal vessels indicates that placenta might play an important role in leptin production. The postnatal leptin decrease may be a physiologically feasible adaptation to profound alterations in fuel homeostasis during the first days of extrauterine life. 1961