NALTREXONE ADMINISTRATION MODULATES THE NEUROENDOCRINE CONTROL OF LUTEINIZING-HORMONE SECRETION IN HYPOTHALAMIC AMENORRHEA

Because endogenous opioids have been considered to be deeply involved as a causal factor of hypothalamic amenorrhoea, this study was designe d to evaluate the efficacy of the administration of naltrexone, an ant agonist of opioid receptors, on luteinizing hormone (LH) secretion in patients with hypothalamic amenorrhoea, A total of 30 patients with hy pothalamic amenorrhoea were studied, Patients were divided into two gr oups: group A, hypogonadotrophic (n = 15), and group B, normogonadotro phic (n = 15), All patients were administered naltrexone at a dose of 50 mg/day per os for 6 months, A third group of 10 amenorrhoeic patien ts was treated with placebo per os with the same schedule, All patient s were evaluated for LH spontaneous pulsatile release in baseline cond itions and after 3 and 6 months of treatment, Plasma gonadal steroid c oncentrations increased significantly in all patients after 3 months o f naltrexone therapy, but only hypogonadotrophic patients showed a sha rp increase in both LH plasma concentrations and LH pulse amplitude wi thin the first 3 months of treatment which remained unchanged until th e sixth month of treatment, Plasma follicle stimulating hormone concen trations did not change significantly in any patient, Menstrual bleedi ng occurred within 90 days of the beginning of treatment in 24 out of the 30 patients, Patients treated with placebo did not show a signific ant change in gonadotrophin and gonadal steroid plasma concentrations, The results of our study support the efficacy of naltrexone administr ation on neuroendocrine pathways controlling LH secretion in patients with hypothalamic amenorrhoea.