CHUNG, Koo-Whang*; MCEDWARD, Lari/A; MOORE, Brandon/C; MILNES, Matthew/R; IGUCHI, Taisen; GUILLETTE, Louis/J; University of Florida: Folliculogenesis of juvenile American alligators (Alligator mississippiensis) and the role of genetic regulation of gonadal hormones in ovarian follicle formation as a study in life history

The development of ovarian follicles in the American alligator does not occur in the embryo. In captive animals, this process begins approximately 6 � 9 months after hatching. To examine this process in more detail, folliculogenesis was examined using two methods, 1) a gross count of follicles in the ovary based on histological sections and 2) quantification of gene expression for factors involved in ovarian follicle formation. A basic understanding of what genes are active during the growth of the ovary has not been examined in detail in any crocodilian species. Our study examined possible correlations between follicular counts and the upregulation of specific genes involved in gonadal development, such as FSH and estrogen receptors, and TGF-β superfamily ligands (inhibin, activin). Also through a study of life history, we will present differential follicular counts by body mass. We observed that animals in the mid weight range (140 grams � 300 grams) exhibited a significant number of follicles (range 0 – 40), whereas animals at the extremes in body size (range 100 g � 140 g and 300 g – 400 g) show very low follicular counts (range 0 – 5). These data suggest a complex interaction between ovarian follicle development and body size.