Inhibition of mid-cycle gonadotrophin release in healthy women by pimozide and fusaric acid.

The effects of pimozide, a drug blocking dopamine receptors, and fusaric acid, an inhibitor of dopamine beta-hydroxylase, on mid-cycle release of FSH and LH were studied in 8 healthy women 20-25 years of age. None had used contraceptive drugs for the preceding 10 months. From the menstrual history and serum LH determinations during the normal cycle, mid-cycle gonadotrophin bursts were predicted for the following three cycles. Two days before and after the expected gonadotrophin surge were regarded as sufficient for the drug tests. Pimozide (initially 2 mg, then 1 mg/day) and fusaric acid (600 mg/day) were administered in a randomized cross-over study. The mid-cycle LH values were reduced from the control level of 56 +/- 10 mIU/ml (mean +/- SE) to 22 +/- 4 mIU/ml by pimozide (P less than 0.001) and to 17 +/- 5 mIU/ml by fusaric acid (P less than 0.001). The serum FSH level was 9 +/- 2 mIU/ml on the day of the LH surge and did not change significantly during treatment with either drug. The LH and FSH responses to synthetic LRF (100 mug iv) were not changed by pimozide or fusaric acid. The rise of basal temperature associated with ovulation was not affected by the drugs. These results suggest that suprapituitary noradrenergic and dopaminergic neurotransmitters are involved in the regulation of mid-cycle gonadotrophin secretion in women.

RCT Entities:   Population Interventions Outcomes