Homeostasis of circulating androgens levels in the male three-spined stickleback (Gasterosteus aculeatus)
2012 (English)In: Zoological Studies, ISSN 1021-5506, Vol. 51, no 8, 1282-1289 p.Article in journal (Refereed) Published
In mammals, plasma androgen levels are regulated by homeostatic feedbackmechanisms operating in the brain-pituitary-gonadal axis. However, some earlierstudies suggest that this may not be the case in all teleosts. This study aims atinvestigating to what extent androgens levels are homeostatically regulated in malethree-spined stickleback (Gasterosteus aculeatus), and whether aromatisation ofandrogens plays a role in this. To that end, breeding male sticklebacks were eithercompletely castrated or hemi-castrated or sham-operated, and implanted with differentdoses of 11- ketoandrostenedione (11KA) and testosterone (T) or with the aromataseinhibitor (AI) fadrozole. Hemi-castration alone diminished androgen levels andcomplete castration almost removed them. Low doses of 11KA and T increasedplasma androgen levels in castrated but not in sham-operated fish. Both low and highdoses of 11KA increased plasma 11-ketotestosterone (11KT) in hemi-castrated fish,whereas only the high dose of 11KA did so in sham-operated fish. If aromatizationplays a role in homeostatic mechanisms, androgen levels would be expected to rise insham-operated fish treated with AI. However, this was not the case. The reduction ofplasma androgen levels in fully mature hemi-castrated fish may suggest that theremaining testis is not able to increase its steroidogenesis further. However, both311KA and T treatments increased plasma levels much less in sham-operated fish thanin castrated ones, indicating that homeostatic mechanisms are nevertheless present.
Place, publisher, year, edition, pages
2012. Vol. 51, no 8, 1282-1289 p.
steroid, RIA, homeostasis, feedback, stickleback
Research subject Zoological physiology
IdentifiersURN: urn:nbn:se:su:diva-80875OAI: oai:DiVA.org:su-80875DiVA: diva2:557928