[Autophosphorylation of erythrocyte insulin receptors in patients with polycystic ovary syndrome].

OBJECTIVE

To investigate the tyrosine autophosphorylation of insulin receptors in patients with polycystic ovary syndrome (PCOS).

METHODS

Forty patients with PCOS and 20 age- and body mass index matched healthy women were included in the study. The patients with PCOS were classified as HI-PCOS (n=20) or non-HI-PCOS (n=20) based on the fasting insulin level (>or< or =15 mIU/L). 1) Serum gonadotropins and ovarian steroids were determined. Oral glucose tolerance tests (OGTT) and insulin releasing tests were performed to calculate the insulin resistance index (HOMA-IR). 2) Blood samples were obtained at five time-points during the OGTT (Fasting and 30 min, 60 min, 120 min, and 180 min after taking 75 g glucose orally). The erythrocytes were isolated and the autophosphorylation insulin receptors (APIR) and total insulin receptors (TIR) were measured by enzymatic immunoassay. 3) The in vivo autophosphorylation of insulin receptors was indicated by the APIR/TIR ratio.

RESULTS

The HI-PCOS patients had lower APIR/TIR ratio than the non-HI-PCOS patients and healthy controls at the 60th minute after OGTT (P<0.05). No differences in other time-points were significant.

CONCLUSION

The autophosphorylation of insulin receptors in HI-PCOS patients decrease, which might be a mechanism for insulin resistance in patients with PCOS.