Date of Award

5-2010

Document Type

Honors Thesis

Degree Name

Bachelor of Science

Department

Biological Science

Abstract

Testosterone (T) can alter sexual, social, anxiety-like, and/or cognitive behavior of male rodents and exert trophic effects on the prostate. However, whether these effects are due to actions of T, or its 5-reduced and/or aromatized metabolites, is of interest. We tested the hypothesis that T’s effects to enhance prostate proliferation, sexual, social, cognitive and/or anti-anxiety-like behavior require formation of 5-reduced and/or aromatized metabolites. Gonadectomized (GDX) or gonadally-intact rats were administered T-containing, or empty, silastic capsules in conjunction with a 5-reductase inhibitor (finasteride; Experiment 1) or an aromatase inhibitor (formestane; Experiment 2). The performance of rats in sexual, cognitive (object recognition, object placement, water maze), anxiety-like (open field, elevated plus maze, light–dark transition, mirror maze, social interaction) tasks were examined. Prostate mass and concentrations of T and its metabolites were assessed. Rats that were GDX, compared to intact rats, had lower androgen levels, smaller prostates, longer latencies to initiate sexual contacts, had poorer cognitive performance in the object placement and water maze tasks, and demonstrated more anxiety-like behavior in the light/dark transition task and the mirror maze. Finasteride produced effects similar to GDX to decrease prostate weight and inhibit sexual behavior and spatial cognition, but not affective behaviors. Formestane did not alter prostate mass or sexual behavior, but did enhance cognitive performance in the object recognition task and tended to increase central entries in the open field, an indication of anti-anxiety behavior. Thus, shunting T’s metabolism from aromatization to favor 5-reduction had beneficial cognitive and anti-anxiety effects without negative effects on prostate or sexual behavior.

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