Unpredictable changes in environment sometimes require rapid flexibility in an animal’s physiological response. Coordinated signaling regulates reproductive physiology via the hypothalamic-pituitary-gonadal (HPG) axis. Gonadotropin-inhibitory hormone (GnIH, mammalian ortholog RFRP-3) is known to inhibit the HPG in many vertebrates; however much remains unknown about its role and responsiveness to physiological challenges, especially in a comparative context. HPA activation and circulating glucocorticoids have been found to increase GnIH content in the brain and gonads of some species, and may suppress reproduction by action in both tissues. Reproductive neuroendocrinology is historically understudied in bats despite interesting annual reproductive life-history patterns of temperate species. Using wild-caught captive big brown bats (E. fuscus) we determined acute stress effects on hypothalamic neuropeptides and gonad function. Male bats were sacrificed immediately (n=8) or subjected to 60 min restraint (n=8) after which whole brains, testes, and blood were sampled. Stress induced a 6-fold increase in corticosterone and rapid decrease in plasma testosterone. RFRP-3, GnRH, and c-Fos cell immunoreactivity was quantified and relative gonadal steroidogenic mRNA expression determined alongside cellular apoptosis markers. Understanding how stress affects bat reproductive physiology will provide knowledge essential to making predictions about individual fitness and, broadly, success of populations in the face of dynamic environments.