Nine amenorrhoeic women with anorexia nervosa (AN) were given long-term treatment with 500 microgram of synthetic luteinizing hormone-releasing hormone (LRH) every 8 h. All the women had impaired luteinizing hormone (LH) secretion and no evidence of endogenous oestrogen production. Three of them also had deficient follicle-stimulating hormone (FSH) secretion. The pituitary reserve capacity for gonadotrophin secretion was normal but the response pattern to LRH was similar to that described in prepubertal girls. The constant administration of LRH normalized basal LH and FSH secretion and induced a cyclical gonadotrophin secretory pattern with differential changes of the LH and FSH responses to LRH during the treatment. LRH-induced gonadotrophin secretion produced follicular growth and maturation in all the women. Presumptive ovulation also occurred during the 8 treatment courses in which only LRH was administered. However, inadequate luteal phases were observed during 6 of these 8 cycles. Combined therapy with LRH and human chorionic gonadotrophin (HCG) during 5 treatment courses resulted in normal ovulatory cycles with adequate corpus luteum function.