Leptin concentration in non-obese and obese children with type 1 diabetes mellitus

Leptin, the product of the ob gene, is an adipocyte-derived hormone that po sitively correlates with body fat percantage and body mass index (BMI). The re are many data which demonstrate a significant relationship between lepti n and insulin, but the mechanism underlying the changes of leptin induced b y insulin and vice versa remains to be studied in more detail. In this review, we analysed the data on the behaviour of serum leptin level s in non-obese and obese children with type 1 diabetes mellitus. It has bee n shown that the diminished serum leptin concentrations in patients with ne wly discovered insulin-dependent diabetes mellitus (IDDM) could he caused b y insulin deficiency and/or increased lipolysis. Moreover, while in some st udies in diabetic children with good metabolic control the serum leptin lev els are similar to those of healthy children, in other studies children wit h IDDM have leptin levels higher than non diabetic children: it is possible that in some diabetic children intensified insulin therapy could cause chr onic hyperinsulinemia with high leptin levels. The mean serum leptin concentrations in the obese diabetic subjects were si gnificantly higher when compared with non-obese diabetics. Obese diabetic p atients showed no significant differences in leptin concentrations in compa rison to the non diabetic obese group matched by age, sex and BMI. In obese diabetics, during weight loss, indepedent of the quality of metabo lic control, serum leptin concentration declines. The changes of leptin in diabetes seem to be similar to those observed in healthy obese subjects. (C ) 2000 Editions scientifiques et medicales Elsevier SAS.