Melatonin inhibitory effect on luteinizing hormone release is potentiated after long pretreatment with the indole.
The effect of melatonin on luteinizing-hormone releasing-hormone stimulation of cyclic AMP accumulation and luteinizing hormone (LH) release from neonatal rat hemipituitaries was studied in vitro. Melatonin inhibited LH-release from pituitaries of animals kept previously on long but not on short photoperiods; cyclic AMP accumulation was, however, inhibited on both photoperiods. There were no daily changes in the melatonin effect. Inhibition of LH-release was strongly potentiated after 6 h preincubation with melatonin as compared with 20 min preincubation; cyclic AMP was not significantly affected by the length of preincubation.
Vanĕcek
J
J
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism*; D008550:Melatonin / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007211:Indoles; D005576:Colforsin; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D000242:Cyclic AMP; D008550:Melatonin