Plasma Leptin, Insulin Resistance, and Obesity Index of Type 2 Diabetics and Normal Subjects among Koreans

Abstract

Background: Leptin has been reported to be correlated with the amount of adipose tissue in humans. The plasma leptin concentrations were not different between diabetics and non-diabetics in Mexican-Americans; however, the leptin might stimulate or diminish insulin secretion and induce insulin resistance. Then, it can be postulated that leptin may one of the key factors in the development of insulin resistance. Therefore we were to note any differences in FPL (fasting plasma leptin levels) between diabetics and normal subjects, and to investigate variables such as PBF (percentage body fat), BM[ (body mass index), FPI (fasting plasma insulin) to determine their effects on the variation of FPL. We also were to investigate whether FPL influenced the GUR (glucose utilization rate). Methods: The subjects were 116 type 2 diabetics and 45 normal subjects in Korean. PBF, BMI, WHR (waist hip ratio) were measured. Fasting plasma insulin and leptin levels were measured by radioimmunoassay. Euglycemic and/or hyperglycemic clamp tests were performed in 19 diabetics and 16 normal subjects. Results: 1. There was no difference in FPL between diabetics and normal subjects. 2. A significant difference was found in FPL between female and male subjects. 3. Gender and body composition such as PBF, BMI contributed plasma leptin levels. 4. FPL was associated with GUR (Insulin resiatance) only in male subjects. 5. During 2h clamp tests, the acute increments of insulin or glucose did not change the leptin levels. Conclusion: These data suggested that there was no difference in FPL between diabetics and normal subjects, whereas gender, body composition such as PBF, BMI contributed leptin levels.