GENDER-SPECIFIC DIFFERENCES OF SERUM LEPTIN IN OBESE AND NORMAL-WEIGHT ADOLESCENTS - STUDIES IN TYPE-I DIABETES AND TURNER-SYNDROME

The influence of exogenous insulin and estrogen substitution on serum leptin-like immunoreactivity was studied longitudinally in patients wi th type-I diabetes and Turner syndrome using a specific radioimmunoass ay. Prepubertal, pubertal and postpubertal samples of 17 patients (9 g irls, 8 boys) with type-I diabetes mellitus developing obesity were co mpared to those of 17 normal-weight controls matched for gender, age a nd diabetes duration. Six obese and six normal-weight girls with Turne r syndrome were studied without hormone substitution, with ethinylestr adiol alone, and with cyclic estradiol/gestagen substitution. The mean leptin levels of the girls with diabetes were two times higher than b oys at all times, while insulin doses and glycemic control had no infl uence. In Turner syndrome estrogen substitution led to increased lepti n levels only in the obese group. This study revealed that both body w eight above normal and female sex steroids seem to be necessary to ele vate leptin concentrations, while exogenous insulin has no effect.