P2.176 Thursday, Jan. 5 The potential role of glucocorticoid signaling during sex determination in the American alligator (Alligator mississipiensis). MCCOY, JA*; KOHNO, S; DOHENY, BD; GUILLETTE, JR., LG; Medical University of South Carolina, OBGYN, Hollings Marine Lab; Medical University of South Carolina, OBGYN, Hollings Marine Lab; Medical University of South Carolina, OBGYN, Hollings Marine Lab; Medical University of South Carolina, OBGYN, Hollings Marine Lab firstname.lastname@example.org
A critical point of vertebrate sex determination occurs when the bipotential gonad develops into a testis or ovary. Although the role of estrogen is important in ovarian development, the complete network of cellular and molecular signals that influence gonadal development remains poorly understood. We use the American alligator to examine questions related to sex determination and gonadal development. This model is useful as sex is determined by the incubation temperature during a thermo-sensitive period (TSP) of embryonic development. During development, the gonad is part of a complex that includes the adrenal gland and mesonephros. Given the proximity of the developing gonad to the adrenal gland and the fact adrenal function is influenced by heat stress, it is feasible to hypothesize that adrenal steroid hormones influence sex determination. Potential mechanisms of adrenal regulation include: (1) production of HSP90α, a modulator of steroid hormone action, and (2) modulation of anti-Mullerian hormone (AMH) activity, which is essential for testicular development. To explore these questions, we have treated developing embryos prior to the TSP (Stage 19) with either a synthetic glucocorticoid (dexamethasone) or corticosterone. The experimental design and findings presented here aim to unravel the signaling pathways involved in environmental sex determination, specifically the potential role of adrenal gland activity on sex determination of the American alligator.