Pituitary and ovarian suppression after early follicular and mid-luteal administration of a LHRH agonist in a depot formulation: decapeptyl CR.

In order to study its effect on pituitary and ovarian function, a single dose of triptorelin depot (Decapeptyl CR, Ferring) was administered to 12 women in the early follicular (EF,n = 6) or mid-luteal phase (ML,n = 6) of a normal cycle. In all 12 women the initial pituitary and ovarian responses were similar. Luteinizing hormone (LH) and follicle stimulating hormone (FSH) rose to peak values within 48 h, and declined to hypogonadotropic levels within 2 weeks' time. Steroid levels showed a slight to marked rise after injection and fell to hypogonadal values within 1 week. LH suppression was maintained until the 8th week after the injection, while FSH levels rose to normal between the 3rd and 4th week. Estrogen secretion started to be restored in the course of the 7th and 8th week. Menses occurred between the 11th and 13th week after the injection of the drug. This study demonstrates the possibility of rapid induction of a hypogonadotropic and hypogonadal condition in regularly cycling women by administration of a single triptorelin depot. Suppression of pituitary and ovarian function appears to be continued until the 8th week after the injection.