Plasma adiponectin levels in women with polycystic ovary syndrome: impact of metformin treatment in a case-control study

Abstract

Objective: An interaction between adiponectin, steroid synthesis or action and measures of insulin resistance (IR) have been reported in the pathogenesis of polycystic ovary syndrome (PCOS). The present study was done to determine plasma adiponectin concentration (PAC) in women with and without PCOS and to assess its correlation to the hormonal and metabolic parameters including measures of IR. The effect of Metformin for 6 months in PCOS was also evaluated.

Patients: In total, 72 selected women were classified as follows: 17 obese (body mass index (BMI))>25 kg/m(2) with PCOS; 19 normal weight (BMI) 18-22.9 kg/m(2) with PCOS; 17 obese (BMI)>25 kg/m(2) without PCOS and 19 normal weight (BMI) 18-22.9 kg/m(2) without PCOS.

Interventions: Blood samples were collected from all women with PCOS between 0800 and 1100 h, after an overnight fast.

Main outcome measures: Serum level of LH, FSH, TSH, total T4, testerosterone, 17-α-hydroxyprogesterone (17OHP), DHEAS, insulin, adiponectin and glucose. Measures of IR included fasting serum insulin (FSI), glucose-to-insulin ratio, and homeostasis model assessment (HOMA).

Result and conclusion: Waist-hip ratio (WHR), insulin, and HOMA index were significantly higher in the lower adiponectin group than in the higher adiponectin group. By using stepwise multiple regression analysis, in model 1 (including BMI, FSI, fasting plasma glucose (FPG) with other variables such serum as testerosterone and DHEAS), the weight and contributions from other variables, namely FSI and FPG were significant independent determinants of fasting PAC (adjusted r(2)=0.66); and in model 2 (including BMI, HOMA, FPG only as an index of IR with other variables such as serum testerosterone and DHEAS), BMI, and HOMA were significant independent determinants of fasting PAC (adjusted r(2)=0.59). FPG, HOMA index and FSI were significantly lower after Metformin treatment in both obese and non-obese PCOS while adiponectin levels increased significantly.