[Hyperinsulinemia and disorders of the menstrual cycle]

Hyperinsulinaemia and insulin resistance are usually associated phenomena of obesity and the polycystic ovary syndrome (PCO syndrome). On the other hand the PCO syndrome and obesity are often associated with disorders of the menstrual cycle and/or sterility. The authors examined 35 women aged 21 to 38 years (x = 27 +/- 4.4) with a history of anovulation cycles and/or sterility. 24 of them (68.6%) suffered from PCO syndrome. Their mean BMI was 28.95 kg/m2. 11 patients had a normal body weight, 6 were overweight and 18 were obese. The authors used the oral glucose tolerance test (oGTT) and during minute 0 and 120 blood samples were collected for assessment of the blood sugar and plasma insulin. Insulin levels in minute 0 (Io above 20 and in minute 120 (I120) above 65 uIU/ml were classified as hyperinsulinaemia. In the follicular stage of the anovulation cycle the authors assessed FSH, LH, testosterone, progesterone and prolactin. Hyperinsulinaemia ws recorded in 16 of 35 women. The mean insulin level at minute 0 was 11.9 +/- 1.3 and during minute 120 54.2 +/- 8.1 uIU/ml. The authors found significant differences in levels of I0 (6.4 +/- 1.2 vs. 16.1 +/- 1.9 uIU/ml, p < 0.01) and I120 (17.5 +/- 3 vs. 71.3 +/- 10.3 uIU/ml, p < 0.01) between obese and non-obese patients, Also in patients with the PCO there was a statistically significant difference in insulin levels of slim (BMI less than 25) as compared with obese women (BMI more than 30) (p < 0.01). A positive correlation was found between insulin levels and BMI (p < 0.01) and a liminal correlation between insulin and testosterone (p = 0.05). Patients with hyperinsulinaemia were treated with oral antidiabetics from the group of biguanides--metformin for a period of three months. During metformin treatment the insulin level declined and subsequently the menstrual cycle became normal in 11 of 16 patients with hyperinsulinaeia (68.7%), incl. two women who became pregnant. The results indicate a possible new indication of metformin in the treatment of ovarian hyperandrogenism in insulin resistant patients.