The effects of ketoprofen on ovarian function in dairy cows

This presentation reviews current information on the events that lead to rupture of an ovarian follicle. It contains a summary of the morphological changes that occur at the apex of a follicle wall during ovulation. Existing information shows that the tenacious connective tissue layers of the tunica albuginea and theca externa must be weakened before the follicle wall can dissociate and break open under the force of a modest intrafollicular pressure. These changes are probably dependent on transformation of quiescent thecal fibroblasts into proliferating cells in a manner that is characteristic of tissue responses to inflammatory reactions. The metabolic factors that initiate transformation of the fibroblasts are uncertain, but they are probably generated by gonadotropin-induced changes in the theca interna and granulosa of a follicle as these layers begin to luteinize during the ovulatory process.

Ovulation is a complex process that is initiated by the lutenizing hormone surge and is controlled by the temporal and spatial expression of specific genes. This review focuses on recent endocrine, biochemical, and genetic information that has been derived largely from the identification of new genes that are expressed in the ovary, and from knowledge gained by the targeted deletion of genes that appear to impact the ovulation process. Two main areas are described in most detail. First, because mutant mouse models indicate that appropriate formation of the cumulus matrix is essential for successful ovulation, genes expressed in the cumulus cells and those that control cumulus expansion are discussed. Second, because mice null for the progesterone receptor fail to ovulate and are ideal models for dissecting the critical events downstream of progesterone receptor, genes expressed in mural granulosa cells that regulate the expression of novel proteases are described.