Inhibition of ovulation in women by chronic treatment with a stimulatory LRH analogue--a new approach to birth control?

A stimulatory luteinizing hormone-releasing hormone (LRH) analogue D-Ser(TBU)6-EA10-LRH was administered subcutaneously once daily in a dose of 5 microgram to four regularly menstruating women. Treatment was instituted within the first three days of the menstrual bleeding and continued for 22--30 days. Ovulation was inhibited in all the women during the treatment cycle. The treatment resulted in disturbances in the pituitary gonadotropin secretion which presumably led to disordered follicular menuration and anovulation. The maximum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) responses to the LRH analogue were obtained during the first few days of treatment. The gonadotropin responses then rapidly decreased during the prolonged treatment. This change in the pituitary responsiveness probably prevented the release of a normal preovulatory LH surge. After the treatment, all the women resumed normal ovulatory menstrual cycles. The results suggest that it might be possible to use stimulatory LRH analogues for birth control.