PLASMA LEPTIN LEVELS IN NEWBORNS FROM NORMAL AND DIABETIC MOTHERS

Leptin can be considered as a peripheral signal which informs the cent ers about the mass of energy stores. Studies done on the human adult p opulation have demonstrated that degree of adiposity and insulin level s play a major role as determinants of leptin circulating levels. The aim of this study was to evaluate which factors may influence leptin l evels at birth, We examined the role played by baby size and by the me tabolic environment the fetus was exposed to during pregnancy. We cons idered 85 newborns from normal (n = 60), gestational (GDM, n = 17) and pregestational (IDDM = 8) diabetes mellitus mothers. At delivery, blo od was taken from the umbilical cord vein. Babies from normal and GDM mothers were subdivided into ACA (appropriate for gestational age) and LGA (large for gestational age). There was no difference in leptin le vels between babies from normal or GDM mothers belonging to the same w eight category, but leptin levels were always higher in LGA than in AC A newborns, and highly correlated with birth weight (r = 0.34, P = 0.0 01). Moreover, IDDM mothers gave birth to newborns with significantly higher levels of leptin and insulin when compared with normal and GDM mothers. Diabetes of both GDM and IDDM mothers was clinically well con trolled (HbA1c was 4.0 and 7.2, respectively). The correlation between leptin and insulin was significant only when newborns from IDDM mothe rs were included in the regression analysis (r = 0.39, P = 0.0002). Ou r results suggest that degree of adiposity is one of the main regulato rs of leptin concentration in the human newborn and that babies expose d to an altered, though clinically controlled, metabolic environment, as in IDDM mothers, have increased levels of leptin.