Gender-Specific Differences of Serum Leptin in Obese and Normal-Weight Adolescents: Studies in Type-I Diabetes and Turner Syndrome

Abstract

The influence of exogenous insulin and estrogen substitution on serum leptin-like immunoreactivity was studied longitudinally in patients with type-I diabetes and Turner syndrome using a specific radioimmunoassay. Prepubertal, pubertal and postpubertal samples of 17 patients (9 girls, 8 boys) with type-I diabetes mellitus developing obesity were compared to those of 17 normal-weight controls matched for gender, age and diabetes duration. Six obese and six normal-weight girls with Turner syndrome were studied without hormone substitution, with ethinylestradiol alone, and with cyclic estradiol/gestagen substitution. The mean leptin levels of the girls with diabetes were two times higher than boys at all times, while insulin doses and glycemic control had no influence. In Turner syndrome estrogen substitution led to increased leptin levels only in the obese group. This study revealed that both body weight above normal and female sex steroids seem to be necessary to elevate leptin concentrations, while exogenous insulin has no effect.

Leptin levels in non-obese and obese children and young adults with type 1 diabetes mellitus

“…Although there was a large overlap in the range of serum leptin concentrations between boys and girls, the mean values for the whole group of males was significantly lower than for the females, in diabetics and in controls. In agreement with recent observations, we suggest that the gender differences in serum leptin concentrations, previously described in adult (15,23,24) and pediatric (12) healthy subjects, is already evident in young patients with IDDM.…”

Does the long-term clinical course of type I diabetes mellitus differ in patients with prepubertal and pubertal onset? Results of the Berlin Retinopathy Study

“…A distinct gender dierence in insulin sensitivity with a decreased insulin-mediated glucose utilization has been previously demonstrated in euglycaemic clamp studies, in particular in female adolescents [3]. Moreover, gender speci®c dierences of other hormones involved in weight regulation and energy expenditure such as leptin have been described in adolescents with diabetes [5]. On the other hand, psychological variables may also be of importance.…”

Leptin levels show diurnal variation throughout puberty in healthy children, and follow a gender-specific pattern

“…In vitro experiments using human adipocytes showed that testosterone is able to reduce leptin secretion (40), while oestradiol induces a notable increase in leptin in women, but does not alter leptin secretion in males (41). On the other hand, oestrogen substitution or suppression does not appear to increase leptin levels in normal-weight humans (19,42). Nevertheless, oestradiol does appear to be involved in the regulation of leptin levels.…”