ALVERS, A.L.**; MOORE, B.C.; MILNES, M.R.; IGUCHI, T; GUILLETTE, L.J.; Univ. of Florida, Gainesville; Univ. of Florida, Gainesville; Univ. of California, Irvine; Okazaki National Research Institutes; Univ. of Florida, Gainesville: Sexually Dimorphic Gonadal Gene Expression in 13 Month Old Alligators

Gonads are hormonally active during embryonic development but then go through a period of quiescence until puberty. Inhibins and activins, members of the TGF-beta family, have the ability to regulate pituitary secretion of FSH and gonadal functions. Previous studies examining chickens have shown differential expression of inhibin alpha and beta A subunits during embryonic development of male and female gonads. However, little is known about the role of inhibins and activins in the postnatal, prepubertal non-reproductive gonad. This study examined sexual dimorphism in gonadal gene expression in prepubertal 13 month old American alligators (Alligator mississippiensis). mRNA expression for the alpha, beta A and beta B subunits of inhibin and activin was quantified through real-time Q-PRC methods for ovarian and testicular tissue. Additionally, expression of ER alpha, ER beta, FSHR and follistatin was quantified using this method as well. Our data indicates that despite the quiescent nature of the gonads during the postnatal prepubertal stages, significant differences in gene expression between sexes was observed. We observed that testicular tissue expressed greater concentrations of the inhibin alpha subunit when compared to ovarian tissue. Future studies need to address these differences as their significance in the maturation and future functioning of the gonad is still unknown.