The goal of this Research Planning Grant (RPG) is to examine the temporal pattern of endogenous gonadotropin-releasing hormone (GnRH) release in the bullfrog, Rana catesbeiana. Ranid flogs are highly unique in that they are the only tetrapods known to date to display a true physiological preference for continuous, rather than pulsatile, GnRH input for the maintenance of gonadotropin secretion. Based on this observation, it is hypothesized that unlike mammals and birds, reproduction in ranid frogs is driven by continuous release of endogenous GnRH. This hypothesis will be tested directly in this Research Planning Grant by investigating the temporal pattern of GnRH release from bullfrog hypothalamic slices using an in vitro perfusion system. The RPG results will provide the physiological basis for future investigations into the mechanisms by which continuous GnRH stimulation supports the overall reproductive functions. In addition, these data will facilitate the understanding of the dynamics of a potentially very novel hypothalamic-pituitary system.
