NALMEFENE ENHANCES LH-SECRETION IN A PROPORTION OF OLIGO-AMENORRHEIC ATHLETES

The influence upon LH secretion of doses of nalmefene, an orally effec tive congener of naloxone, and a placebo was compared in nine oligo-am enorrheic athletes with that in five regularly menstruating non-athlet ic women as a test for periodic elevations in hypothalamic opioid tone . After a 360-min control period, LH levels were followed for an addit ional 360 min following ingestion of the medications in random order a pproximately six weeks apart, 10-min blood sampling being employed thr oughout. The mean amplitude post-nalmefene in the athletes was signifi cantly greater than pre- (p<0.05), although there were no differences in the frequency of LH pulses after placebo or nalmefene ingestion. Su bjects were labelled as ''responders'' if their peak AUC after treatme nt exceeded their pretreatment AUC for LH by more than 1.96 SD (p<0.05 ). There were no placebo responders, but 5/9 of the athletes and 1/5 o f the menstruating controls were classified as nalmefene responders (p <0.05). In addition, a variable proportion of the athletes (but none o f the controls) experienced symptoms suggestive of narcotic withdrawal 1-4 h after ingesting nalmefene and again 12-18 h later. It appears t hat demonstrable increases in opioid tone occur at least transiently i n a proportion of oligo-amenorrheic athletes.