SERUM LEPTIN CONCENTRATION IS ASSOCIATED WITH TOTAL-BODY FAT MASS, BUT NOT ABDOMINAL FAT DISTRIBUTION

OBJECTIVE: The obese (ob) gene encodes leptin which inhibits appetite and stimulates thermogenesis. Serum leptin concentrations are determin ed by total body fat mass, but the influence of visceral fat accumulat ion and other metabolic factors have not been clinically determined. M ETHODS: We determined the correlations between serum leptin concentrat ions and the total body fat mess, abdominal fat mass, abdominal Sat di stribution (estimated by ultrasound), and circulating metabolic factor s in 104 Japanese healthy subjects (11 men and 93 women). In addition, the effect of food restriction (30 kcal/kg desired body weight/day) f or four weeks on serum leptin concentrations were also examined in 30 women. RESULTS: There was a significant correlation between serum lept in concentrations and total body fat mass (r = 0.708, P < 0.0001), the percentage of body fat (r = 0.561, P < 0.001), and the body mass inde x BMI, r = 0.630, P < 0.001). Serum leptin concentrations were correla ted with the abdominal wall preperitoneal and subcutaneous fat pad thi ckness, but not the abdominal wall fat index (AFI). Serum leptin conce ntrations were also correlated with serum immunoreactive insulin (IRI) , but not glucose, Or free fatty acid (FFA) concentrations. The weight less after food restriction for four weeks significantly (P = 0.016) reduced the serum leptin concentrations with a significant reduction o f body fat mass, serum glucose, IRI and FFA concentrations. However, t here was no significant correlation of the percentage change in serum leptin concentrations to that in body fat mass after food restriction. CONCLUSION: Serum leptin concentrations are well correlated with the total body dat mass in healthy subjects. Differences in abdominal fat distribution do not appear to be related to a difference in the in viv o leptin production from adipose tissue.