Pending FDA approval, pST will be used in commercial swine operations as a tool to increase the efficiency of swine production. Our long term goals are to understand the actions of ST on reproductive functions in swine, and other domestic species. In this proposal, our primary objective is to further elucidate the role of ST as a molecular modulator of sterol metabolism and ovulation propensity in the ovaries of swine, and a bST-transgenic mouse model. We have selected a parameter of reproductive function which has considerable economical importance to the swine industry, namely ovulation rate. Specifically, this research is designed to define cellular events that determine follicle recruitment for ovulation versus follicle atresia in laboratory and domestic species.
Follicular atresia is mediated by apoptosis or programmed cell death.
If apoptosis could be decreased, follicular survival would increase, thus increasing the propensity for ovulation. An average increase of one pig per litter nationwide would allow us to produce the currently produced 110 million market pigs with fewer sows than presently required for this level of production. Therefore, the research in this study will improve efficiency of pork production, a pork producer priority. ST-transgenic mice are exposed to very high amounts of circulating ST throughout their entire postnatal life yielding information on the potential consequences of maximal ST stimulation. Maximal responses provide a good starting point for mechanistic studies.