Regulation of the endocrine stress response and the modulating effects of sex steroids in zebrafish (Danio rerio)

The purpose of this study was to characterize the endocrine stress response of zebrafish (Danio rerio) and to test if this response is modified by sex or the major sex steroids 17?-estradiol (E2) and 11-ketotestosterone (11KT). A standardized stress of having zebrafish swim in a beaker of stirring water resulted in rapid and transient changes in whole-body cortisol. While the cortisol response of males and females were comparable, exposure to E2 (100 ng/L) for 48 h inhibited the cortisol response of males and exposure to 11KT (100ng/L) for 48 h stimulated the cortisol response of females. The inhibitory actions of E2 were mediated in part by decreases in corticotropin releasing factor (crf) expression and decreases in the synthesis of cortisol by interrenal tissue. This research adds to the increasing knowledge of zebrafish physiology and will be useful for future studies concerning the endocrine stress response in fish.