[The effects of hyperinsulinmia and insulin-like growth factor-1 on hyperandrogenism in polycystic ovarian syndrome].

OBJECTIVE

To investigate the effects of insulin (INS) and insulin-like growth factor-1 (IGF-1) on ovarian androgen production in women with polycystic ovarian syndrome (PCOS).

METHOD

48 patients with PCOS were divided into two groups based on body mass index (BMI) (24 were obese BMI > 25 and 24 nonobese) (BMI < 25). 10 women with normal weight and menstruation were recruited as controls. The serum LH, FSH and testosterone (T) levels were determined. 40 cases were measured INS, IGF-1, androstenodine (A) and sex hormone binding globulin (SHBG) after a 3-hour oral glucose tolerance test (OGTT). Ovarian stroma obtained from 10 patients with PCOS and 5 healthy women were cultured in the medium with high INS concentration (30 ng/ml and 60 ng/ml). The IGF-1 and A levels were determined.

RESULTS

Two groups of patients with PCOS demonstrated significant hyperinsulinmia (HI) and hyperandrogenism. Significantly higher IGF-1 level was observed in nonobese patients (P < 0.01). Insulin markedly stimulated release of IGF-1 (4 times, P < 0.01) and A (6 times, P < 0.05) in incubation of ovarian stroma obtained from PCOS patients. A positive correlation between IGF-1 and A was present in the culture medium (r = 0.679, P < 0.05). The serum levels of SHBG were significantly lower in PCOS patients.

CONCLUSION

The findings suggest that the women with PCOS have HI, since INS may play an important role in hyperandrogenism by upregulating IGF-1 system in ovary.