Insulin-induced capillary recruitment is impaired in both lean and obese women with PCOS

Abstract

Background Insulin resistance, i.e. impaired insulin-mediated glucose uptake (IMGU), is a major risk factor for type 2 diabetes in women with polycystic ovary syndrome (PCOS). Insulin-induced capillary recruitment (IICR) is considered a significant determinant of IMGU. We investigated whether IICR is a determinant IMGU in obese and lean women with and without PCOS. Methods The study included 36 women with PCOS (20 lean, BMI 21.9 ± 2.3 kg/m 2 and 16 obese, BMI 35.9 ± 6.0 kg/m2) and 27 age-matched healthy controls (14 lean, BMI 22.2 ± 1.8 kg/m2 and 13 obese, BMI 40.5 ± 7.0 kg/m2). IICR was evaluated by capillary microscopy during an isoglycemic-hyperinsulinemic clamp. IMGU was expressed as M/I value. Results The M/I value was significantly lower in obese PCOS women compared with obese controls [0.5 (0.21.1) versus 0.8 (0.31.4) (mg kg-1 min-1 pmol l-1) × 100, P < 0.01], whereas the small difference between lean PCOS and lean control women was non-significant [1.5 (0.52.6) versus 1.7 (1.03.7) (mg kg-1 min -1 pmol l-1) × 100, P 0.17]. Hyperinsulinemia increased capillary recruitment in lean controls (53.5 ± 20.3 versus 64.9 ± 27.4 n/mm2, P < 0.05), but not in either PCOS group nor in obese controls. IICR and androgens were a determinant of M/I value only in lean women with or without PCOS. Conclusions PCOS per se is associated with impaired IICR. Obese women with PCOS, in part independent of obesity, demonstrated a profound insulin resistance, whereas the difference between lean PCOS women and healthy controls was small and statistically non-significant. IICR was a determinant of IMGU in lean, but not in obese, women regardless of the presence of PCOS. © 2011 The Author.