title: The effect of methionine enkephalin on prolactin and luteinizing hormone levels in intact and castrated rats.
abstract: The methionine enkephalin (ME) induced responses of prolactin (PRL) and luteinizing hormone (LH) were studied in control and castrated rats bearing chronically-implanted cannulae in the right lateral ventricle. In control rats, 500 microgram ME caused a rise in PRL from a mean +/- SD basal value of 22.8 +/- 12.2 ng/ml to a peak of 195.2 +/- 93.8 ng/ml (p less than 0.001). The peak control occurred 10 min after ME administration and was short-lived. In the same rats, 14 days after castration, there was a significant reduction in both basal (p less than 0.001) and peak PRL response to ME (p less than 0.01), similar to that previously observed with other PRL-inducing stimuli. LH levels, on the other hand, were unaffected by ME treatment in both control and castrated rats.
mesh_terms: D000818:Animals; D002369:Castration; D004723:Endorphins / Q000494:pharmacology*; D004744:Enkephalin, Methionine; D004745:Enkephalins / Q000494:pharmacology*; D007700:Kinetics; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D011388:Prolactin / Q000097:blood*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D004723:Endorphins; D004745:Enkephalins; D004744:Enkephalin, Methionine; D011388:Prolactin; D007986:Luteinizing Hormone