Subcutaneous adipocytes from obese hyperinsulinemic women with polycystic ovary syndrome exhibit normal insulin sensitivity but reduced maximal insulin responsiveness.

Background: Polycystic ovary syndrome (PCOS) has a high prevalence in women and is often associated with insulin resistance and hence with aspects of the so-called metabolic syndrome.

Methods: Ten women diagnosed with PCOS were consecutively included (aged 21-39 years, average 30.2 +/- 1.9 years; body mass index 28.4-42.5 kg/m2, average 37.5 +/- 1.7 kg/m2 (mean +/- s.e.)). Adipocytes were isolated from the subcutaneous fat and, after overnight incubation to recover from insulin resistance due to the surgical cell isolation procedures, they were analyzed for insulin sensitivity.

Results: The patients with PCOS exhibited marked clinical hyperinsulinemia with 3.6-fold higher blood levels of C-peptide than a healthy lean control group (1.7 +/- 0.2 and 0.5 +/- 0.02 nmol/l respectively, P < 0.0001). The patients with PCOS also exhibited 2.4-fold higher concentrations of serum triacylglycerol (2.1 +/- 0.3 and 0.9 +/- 0.06 mmol/l respectively, P < 0.0001), but only slightly elevated blood pressure (118 +/- 12/76 +/- 6 and 113 +/- 7/72 +/- 6 mmHg respectively, P = 0.055/0.046). However, insulin sensitivity for stimulation of glucose transport in the isolated adipocytes was indistinguishable from a non-PCOS, non-diabetic control group, while the maximal insulin effect on glucose uptake was significantly lower (2.2 +/- 0.2- and 3.8 +/- 0.8-fold respectively, P = 0.02).

Conclusions: Subcutaneous adipocytes from patients with PCOS do not display reduced insulin sensitivity. The findings show that the insulin resistance of PCOS is qualitatively different from that of type 2 diabetes.