The effect of testosterone and season on prodynorphin messenger RNA expression in the preoptic area-hypothalamus of the ram

Chris J Scott, Iain James Clarke, Alan John Tilbrook

Research output: Contribution to journalArticleResearchpeer-review

6 Citations (Scopus)


Testosterone and season influence mRNA expression for the opioid, enkephalin, in the preoptic area and hypothalamus of rams. Dynorphin is another opioid which has been shown to play a role in the control of reproductive function in females. We now report effects of season and testosterone on the expression of prodynorphin mRNA in the hypothalamus of the ram. Castrated adult Romney Marsh rams (5/group) received vehicle or testosterone propionate (i.m.) during either the breeding season or non-breeding season. Prodynorphin mRNA expression was quantified in the hypothalami by in situ hybridisation. Testosterone treatment increased prodynorphin mRNA expression in the supraoptic nucleus and the bed nucleus of the stria terminalis in the breeding season but not during the non-breeding season. Prodynorphin mRNA expression was also higher in the breeding season than in the non-breeding season in the caudal preoptic area, paraventricular nucleus and accessory supraoptic nucleus, irrespective of treatment. No effects of treatment were observed in any other regions of the hypothalamus. We conclude that testosterone and season regulate prodynorphin mRNA expression in a region-specific manner, which may influence seasonal changes in reproductive function.
Original languageEnglish
Pages (from-to)440 - 450
Number of pages11
JournalDomestic Animal Endocrinology
Issue number4
Publication statusPublished - 2008

Cite this