Chronic morphine and testosterone treatment: effects on norepinephrine and serotonin metabolism and gonadotropin secretion in male rats.
The effects of sustained-release implants of morphine (M) and/or testosterone (T) on serum gonadotropin levels and norepinephrine (NE) and serotonin (5-HT) metabolism in brain regions were examined. While 4 days of M or 5 mm [corrected] T treatment were without significant effect, the combination dramatically decreased circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Castration increased NE content of the mediobasal hypothalamus (MBH), and although M, 5 mm [corrected] T, or their combination significantly reduced NE levels in the MBH, they remained elevated compared to intact or 30 mm [corrected] T-treated rats. Further, in the MBH no differences in normetanephrine (NME) levels, nor in NME:NE ratios, nor 5-HT metabolism were evident. In the preoptic area-anterior hypothalamus, NE or 5-HT metabolism were not altered by castration and M and/or T. These results show that M and T interact to suppress LH and FSH release in the apparent absence of any appreciable effect on hypothalamic monoamines.
Gabriel
S M
SM
Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville 32610.
Clark
J T
JT
Kalra
P S
PS
Kalra
S P
SP
Simpkins
J W
JW
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism*; D009647:Normetanephrine / Q000378:metabolism; D051381:Rats; D012016:Reference Values; D012701:Serotonin / Q000378:metabolism*; D012826:Silicone Elastomers; D013739:Testosterone / Q000494:pharmacology*
D012826:Silicone Elastomers; D009647:Normetanephrine; D012701:Serotonin; D013739:Testosterone; D006897:Hydroxyindoleacetic Acid; D009020:Morphine; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D009638:Norepinephrine