Testosterone and GHRH gene expression in adult and old rats.
The effect of castration and testosterone replacement on GHRH gene expression was evaluated in adult male rats. Castration for 21 days did not affect GHRH mRNA levels, and also ineffective in this context was acute or chronic administration of testosterone to castrated rats. Hypothalamic GHRH mRNA was significantly reduced in aged male rats, but restoration of plasma testosterone concentrations via implanted capsules did not modify the low levels of GHRH mRNA. All in all, these findings support the notion that in adult and aged male rats GHRH-producing structures are insensitive to androgens.
De Gennaro Colonna
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Department of Pharmacology, Chemotherapy and Toxicology, University of Milan, Italy.
Cocchi
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D
Lima
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Maggi
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A
Müller
E E
EE
D000375:Aging / Q000235:genetics / Q000378:metabolism; D000818:Animals; D004351:Drug Resistance; D015870:Gene Expression / Q000187:drug effects; D013007:Growth Hormone-Releasing Hormone / Q000235:genetics*; D008297:Male; D009919:Orchiectomy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013739:Testosterone / Q000494:pharmacology* / Q000502:physiology
D012333:RNA, Messenger; D013739:Testosterone; D013007:Growth Hormone-Releasing Hormone