Leptin Concentration in Diabetin and Non-diabetin Subjects in the Community Population

Lee, Kee Up; Hong, Seong Kwan; Kim, Sang Wook; Kim, Young Il; Chung, Yun Ey; Lee, Moo Song; Park, Joong Yeoul; Kim, Jin Yup

Abstract

BACKGROUND: It has been suggested that adipose tissue releases leptin, a satiety factor, which circulates in blood and acts on the hypothalamus to suppress appetite. However, serum leptin concentration in obese human subjects is higher than that in lean subjects, suggesting leptin resistance. Although there have been several studies investigating serum leptin concentrations in Korean subjects, there has been no population-based study. This study was undertaken to investigate serum leptin concentration and associated factors in diabetic and non-diabetic subjects living in a rural area of Korea. METHOD: Among 898 subjects originally included in the Jung-up epidemiologic study, 119 men and 124 women with varying degrees of glucose tolerance were randomly selected. Serum leptin concentration was measured by radioimmunoassay. RESULTS: In agreement with previous studies, women had significantly higher serum leptin concentration than men. Serum leptin concentration in Korean men and women was apparently lower than in other populations, even after adjustment for BMI. Leptin concentration was not different among the three groups of glucose tolerance (normal glucose tolerance, impaired glucose tolerance and diabetes). Serum leptin concentration was positively correlated with serum true insulin, proinsulin and BMI in non-diabetic subjects. Serum leptin concentration was also significantly related with serum proinsulin/true insulin ratio in non-diabetic women. CONCLUSION: Serum leptin concentration in Korean subjects was lower than that reported in other populations. Serum leptin concentration was associated with BMI, serum true insulin and proinsulin levels in non-diabetic subjects, but not in diabetic ubjects.