The regulation of stress steroid release in freshwater turtles

The goal of this study is to characterize the Hypothalamic-Pituitary-Adrenal (HPA) axis regulators of the stress response in a turtle species, the Red-Eared slider, Trachemys scripta elegans and to determine if NPY acts as a secretagogue for adrenal steroids in reptilian species, as it does in mammals. Here, I caught turtles using baited hoop traps. Then, I used pharmacological injections of ACTH (intermediate in HPA axis), dexamethasone (DEX, a synthetic steroid that blocks ACTH release and induces HPA negative feedback), NPY (starvation hormone), and NPY receptor agonists. Each turtle received a single injection upon capture, and I recorded whether adrenal steroid secretion is stimulated or decreased due to negative feedback. The measured changes in adrenal secretion suggested two specific conclusions: 1) A novel connection between the starvation and stress response 2) There may be two independent pathways for stress hormone synthesi