Role of adiponectin and its receptor in prediction of reproductive outcome of metformin treatment in patients with polycystic ovarian syndrome

Abstract

The aim of this study was to examine the effect of metformin on serum adiponectin and adiponectin receptor-1 (AdipoR1) and evaluate their role in prediction of ovulation in patients with polycystic ovarian syndrome (PCOS). The study cohort included 68 PCOS patients with clomiphene citrate resistance (group 1) and 28 healthy women as controls (group 2). Baseline serum adiponectin, AdipoR1, total testosterone (T), and homeostasis model of insulin resistance (HOMA-IR) were measured in all participants. Group 1 received metformin (1500 mg/day) for 6 months followed by second blood sampling. Group 1 had significantly lower baseline adiponectin and AdipoR1 (P = 0.001) compared to group 2. During treatment, metformin resulted in conception in 5/68 (7%), ovulation in 33/68 (48%) and regular cycles in 41/68 (60%) patients. Group 1 showed post-metformin higher adiponectin and AdipoR1 (P = 0.01) and lower HOMA-IR (P = 0.006) and T (P = 0.001) compared to pre-treatment levels. Post-metformin ovulatory patients had higher adiponectin and AdipoR1 and lower HOMA-IR and T compared to anovulatory patients. Multivariate regression analysis in group 1 showed that only T and HOMA-IR were significant independent factors for predicting ovulatory cycles during metformin treatment (P = 0.04 and P = 0.05, respectively). Metformin treatment enhances both adiponectin activity and insulin sensitivity, resulting in a less hyperandrogenic state in patients with PCOS. Serum adiponectin and AdipoR1 are poor predictors of ovulatory outcome during treatment.