Principal Investigator: Joanne Fortune
Contact Information: E-mail: jfl1@cornell.edu - Phone: 607-253-3466
Sponsor: U. S. Department of Agriculture (USDA) Cooperative State Research Education and Extension Service (CSREES)
Grant Number: 2008-35203-05989
Title: Effects of Fetal Steroids on the Formation of Bovine Ovarian Follicles and on their Competence to Initiate Growth
Annual Direct Cost: $64,119
Project Period: 09/1/09-08/31/12
DESCRIPTION (provided by applicant): Establishment of a stockpile of primordial follicles, capable of initiating growth and potentially developing to the preovulatory stage, is a prerequisite for female reproductive success. However for non-rodent species, nothing is known about the regulation of these critical steps in gonadal development. In cattle and other species of practical importance, ovarian follicles form during fetal life, in contrast to their post-natal development in rodents. We have developed an experimental model in which formation of primordial follicles and development of their capacity to activate (i.e., initiate growth) occur in vitro. Our preliminary data suggest the overall hypothesis that steroids produced by the fetal bovine ovary, particularly estradiol and progesterone, regulate both follicle formation and competence to activate. We propose two specific aims to test that hypothesis. In Specific Aim #I, experiments to test the hypothesis is that a decline in ovarian production of estradiol, and perhaps progesterone, initiates follicle formation in vivo are proposed. Based on preliminary results, we propose experiments in Specific Aim #2 to test the hypotheses that ovarian steroids (estradiol and progesterone) inhibit the activation of newly formed primordial follicles and that they do this by inhibiting or delaying the progression of prophase I of meiosis. According to our working model, the gradual decline in ovarian production of estradiol and progesterone, just before and during the time when primordial follicles are forming, first allows follicle formation to occur and then promotes the development of follicular competence to activate.