Serum leptin concentrations in young insulin-sensitive and insulin-resistant volunteers.

The aim of this study was to compare metabolic profiles and serum leptin concentrations between young insulin-sensitive and insulin-resistant subjects. A cross-sectional study was performed in 32 healthy, non-obese, young volunteers. Assessing of insulin sensitivity, serum leptin concentration, serum uric acid, creatinine levels and lipid profile were done on all subjects. An insulin suppression test modified with octreotide was performed to assess insulin sensitivity. Steady state glucose (SSG) and steady state insulin concentrations were calculated. Based on the SSG data, the volunteers were divided into four quartiles, considering as insulin-sensitive individuals those from quartile 1 to quartile 3, and insulin-resistant subjects those in quartile 4. Characteristics of both groups were compared, including metabolic profile and leptin levels. After dividing SSG into quartiles, 24 subjects were considered as insulin-sensitive individuals, and 8 were assessed as insulin-resistant subjects. Total cholesterol and low-density lipoprotein (LDL) cholesterol were significantly higher in the insulin-resistant group than in the insulin-sensitive group. Serum leptin concentration was significantly higher (p=0.05) in insulin-resistant women (6.1 +/- 3.1 ng/ml) than those considered as insulin-sensitive (3.7 +/- 2.3 ng/ml). In conclusion, insulin-resistant subjects had higher concentrations of total cholesterol and LDL-cholesterol compared to insulin-sensitive individuals. Serum leptin level was higher in insulin-resistant women than those considered as insulin-sensitive.