Meeting Abstract

P3.174  Sunday, Jan. 6  Exogenous corticosterone reduces circulating testosterone but not courtship behavior in male zebra finches (Taeniopygia guttata) FERGUSON, S.M.*; LYNN, S.E.; University of Memphis; College of Wooster s.ferguson@memphis.edu

Among vertebrates, environmental stressors can simultaneously activate the hypothalamo-pituitary-adrenal (HPA) axis, inhibit hypothalamo-pituitary-gonadal (HPG) axis activity, and alter reproductive behavior. For example, previous studies in zebra finches have shown that short-term fasting is a physiologically relevant stressor that increased total and free circulating CORT, decreased circulating T, and dampened courtship behavior. However, whether a direct relationship among CORT, T, and courtship behavior exists in this species is unclear. We specifically examined the effects of elevated CORT on both circulating T and courtship behavior in male zebra finches that had established pair bonds with females. We implanted males with CORT-filled silastic implants or empty implants (controls). Twenty-four hr post-treatment, when CORT levels in males reached a peak typical of fasting CORT levels in this species, females were removed from their mate’s cage for 4 hrs. We then returned females to the male’s cage, recorded courtship behavior for 15 min, and collected blood samples for hormone analysis. Males with elevated CORT due to implants (high CORT males) had lower circulating T concentrations than males with baseline CORT (low CORT males). However, courtship behaviors exhibited towards mates did not differ between high and low CORT males. Our results demonstrate that although elevated CORT resulted in dampened levels of circulating T, changes in CORT and T concentrations alone were not sufficient to influence behavior.