Meeting Abstract

146.5  Monday, Jan. 7  Rapid neurosteroidal regulation of paternal care PRADHAN, DS*; SOLOMON-LANE, TK; WILLIS, MC; GROBER, MS; Georgia State Univ.; Georgia State Univ.; Georgia State Univ.; Georgia State Univ. dpradhan1@student.gsu.edu

In vertebrates, shifts in profiles of circulating steroid hormones are critical for reproductive success because they regulate fundamental aspects of reproductive life-history/phenotype. Analyses of region-specific expression and activity of steroidogenic enzymes in the brain have confirmed both the presence of locally regulated steroidal signaling and the importance of neurosteroids for regulating behavior. Thus, rapid control of sex-specific reproductive behavior is likely driven by neural rather than gonadal hormones. Here, we demonstrate neuroendocrine regulation of paternal care in a highly social, polygamous marine fish, the bluebanded goby (Lythrypnus dalli), by in vivo neurochemical manipulation of males in social groups. Parenting was perturbed by modulation of local levels of steroids in the brain via intracerebroventricular injection of a critical enzyme blocker that elevates stress hormones and decreases androgens. Males treated with the drug took longer to enter their nest and had dramatically reduced egg care bouts. Social behaviors, such as agonistic interactions and courtship, remained unaffected. To determine which pathway was involved in inhibiting parenting in our manipulation, we tested two alternate hypotheses. We did not observe a significant reduction in parenting after injection of the glucocorticoid, cortisol. Injection of 11-ketotestosterone, an androgenic product of enzyme synthesis, along with the enzyme inhibitor reversed the negative effects on parenting. Our results show that brain-derived hormones are sufficient to regulate a crucial reproductive behavior, brain androgens directly regulate parenting behavior, and the speed of behavioral effects are consistent with non-genomic mechanisms.