Gonadotrophin control of ovarian follicle growth in cattle

The growth development and maturation of ovarian follicles is a fundamental process for effective reproduction in mammalian species. Initial stages of follicle growth occur independent of gonadotrophic hormones (follicle-stimulating hormone; FSH; and luteinizing hormone; LH), antral follicles then become responsive to and subsequently dependent on FSH. In heifers, there are usually 2-3 waves of gonadotrophin dependent follicle growth during the oestrous cycle each involving emergence of the wave, selection of the dominant follicle (DF) and a period of dominance, followed by either atresia or ovulation of the DF. While the temporal changes in FSH and LH have been well characterized relative to growth of ovarian follicles, the precise mechanisms by which the gonadotrophic hormones act in regulation of the processes of emergence, selection and dominance remains to be elucidated. 

The aims of this project are to determine the molecular mechanisms by which follicle growth occurs in cattle, various physiological models in cattle are used to address the key mechanisms of action. To date a number of key genes have been targeted as being potential regulators of these processes. 

Technologies employed: ovarian ultrasound scanning, pulsatile infusion, immunoassays for key reproductive hormones, and molecular biology techniques such as in-situ hybridization, northern blotting and western blotting. 

Main collaborative partners: University of Michigan, Michigan State University and University of Missouri. 
 

Contact: Mark Crowe