The effect of morphine on the electrophysiological activity of the hypothalamic luteinizing hormone-releasing hormone pulse generator in the rhesus monkey.

In ovariectomized rhesus monkeys, the electrophysiological manifestation of luteinizing hormone-releasing hormone (LHRH) pulse generator activity was arrested by morphine and reinitiated by naloxone. These responses were noted within 1 and 2 min, respectively, after the intravenous injection of the drugs. Naloxone given alone had no effect. These results support the view that opioids modulate pulsatile gonadotropin release by an action on the hypothalamic LHRH pulse generator.