ABSENCE OF INHIBITION BY HYPERPROLACTINAEMIA ON OVARIAN RESPONSE TO EXOGENOUS GONADOTROPHIN

Abstract

ABSTRACT In order to assess the effect of hyperprolactinaemia on the ovarian response to exogenous gonadotrophin, serum oestrogen levels were determined in 6 normal females. Two hundred and twenty-five IU of human menopausal gonadotrophin (hMG) was im injected daily for 3 days from the 4th day of the menstrual cycle, and the serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL) and oestradiol-17β were determined by radioimmunoassay daily for 7 days starting from the first day of injection (control cycle). After 2 months the same schedule was applied to the previous 6 subjects and in addition sulpiride 100 mg bid was given orally during the course of the study (sulpiride cycle). There was a significant increase in serum FSH and a decline in serum LH during hMG treatment in both groups. The mean (± se) serum levels of PRL in the sulpiride group increased gradually from 24.5 ± 3.8 ng/ml (1st day) to 56.2 ± 3.4 ng/ml (7th day). All these levels were significantly higher than those of the control group. The mean (± se) serum oestradiol increments by hMG stimulation in control and sulpiride groups showed a peak on the 5th day with respective levels of 757.2 ± 202.3 and 845.3 ± 263.3 pg/ml. No significant differences in the mean oestradiol increment were found between the two groups on any day. These results indicate that acute hyperprolactinaemia does not appear to induce ovarian refractoriness to exogenous gonadotrophin in normal cyclic women.