Effects of repeated morphine administration on copulation and on the hypothalamic-pituitary-gonadal axis of male rats.
Adult male rats were administered morphine twice a day for 45 days and the effects of morphine on the copulation rate, the weight of various organs, and on the hypothalamic-pituitary-gonadal axis were examined. Morphine administered rats showed a loss of weight, hypertrophy of the adrenals, decreased weight of accessory sex organs, low sperm count, and decreased copulation rate. The contents of the luteinizing hormone releasing hormone in the hypothalamus and the luteinizing hormone in the pituitary remained unchanged. Serum luteinizing hormone and testosterone levels decreased, but serum follicle-stimulating hormone levels increased. These results suggest that morphine inhibits the hypothalamic-pituitary-gonadal axis and causes a diminution in the number of fertilizations of the partner females.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003307:Copulation / Q000187:drug effects*; D005260:Female; D005837:Genitalia, Male / Q000187:drug effects*; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis; D007031:Hypothalamus / Q000032:analysis / Q000187:drug effects*; D007986:Luteinizing Hormone / Q000032:analysis / Q000097:blood; D008297:Male; D009020:Morphine / Q000008:administration & dosage* / Q000494:pharmacology; D009929:Organ Size / Q000187:drug effects; D010902:Pituitary Gland / Q000032:analysis / Q000187:drug effects*; D011247:Pregnancy; D051381:Rats; D012669:Seminal Vesicles / Q000473:pathology; D013739:Testosterone / Q000097:blood
D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D009020:Morphine; D007986:Luteinizing Hormone