Effects of naloxone, morphine and methionine enkephalin on serum prolactin, luteinizing hormone, follicle stimulating hormone, thyroid stimulating hormone and growth hormone
Bruni, J.F.; Van Vugt, D.; Marshall, S.; Meites, J.
Life Sciences 21(3): 461-466
ISSN/ISBN: 0024-3205 PMID: 895378 DOI: 10.1016/0024-3205(77)90528-8
The response of 5 anterior pituitary hormones to single injections of naloxone, morphine and metenkephalin administration was measured in male rats. Morphine and met-enkephalin significantly increased serum prolactin and GH [growth hormone] concentrations and significantly decreased serum LH [luteinizing hormone] and TSH [thyroid stimulating hormone] concentrations. Naloxone reduced serum prolactin and GH concentrations, increased serum LH and FSH [follicle-stimulating hormone], but had little effect on serum TSH concentrations. Concurrent injections of naloxone with morphine or met-enkephalin reduced the response to each of the drugs given separately. Endogenous morphinomimetic substances may partipate in regulating secretion of anterior pituitary hormones.