Reversible hypogonadism induced by a luteinizing hormone-releasing hormone (LH-RH) agonist (Buserelin) as a new therapeutic approach for endometriosis.

Ten women with endometriosis (stages I to IV) were treated with twice-daily subcutaneous injections of 200 micrograms of (D-Ser[TBU]6-des-Gly-NH2(10] luteinizing hormone-releasing hormone ethylamide (Buserelin) for 5 days followed by 400 micrograms intranasally three times daily for 25 to 31 weeks. Serum follicle-stimulating hormone levels returned to basal values on the second day of treatment, and serum luteinizing hormone levels progressively decreased to normal within 4 weeks. Serum estradiol decreased below early follicular phase levels within 7 to 30 days and continued to decrease to castrate levels. Light to moderate estrogen withdrawal bleeding was followed by amenorrhea with occasional bleeding or spotting in four women. Abdominal pain and dyspareunia disappeared or were ameliorated after 2 months of treatment. Resorption of endometrial implants was demonstrated by laparoscopy, and endometrial biopsy revealed atrophy or weak proliferation. Ovulation returned within 45 days, and two of four sexually active women became pregnant during cycles 3 and 5. The treatment was well accepted in spite of the expected hot flushes and vaginal dryness. Safety laboratory tests during and after treatment did not reveal any abnormalities. Reversible down-regulation of pituitary/ovarian function using repetitive luteinizing hormone-releasing hormone agonist administration can be a worthwhile approach to medical treatment of endometriosis.