A major goal of my research program is to identify molecules and metabolic pathways that participate in the control of oocyte maturation in mammals. We have generated considerable data implicating carbohydrates and amino acids as important participants in meiotic regulation, although specific mechanisms of action have not yet been delineated. The experiments proposed herein will address specific questions relating to the involvement of three potential energy substrates--pyruvate, glucose and glutamine--in oocyte maturation. First, an analysis will be made of pyruvate and glucose consumption by oocytes and oocyte-cumulus cell complexes as it relates to meiotic maturation. The hypothesis to be tested is that different energy requirements exist at different stages of meiotic maturation, specifically, that pyruvate requirements increase as the oocyte progresses to metaphase II. Second, the role(s) of amino acids in meiotic maturation will be assessed, with special emphasis on glutamine, utilizing metabolic assays and HPLC analysis of amino acid dynamics. The data will provide insights on the interaction between cumulus granulosa cells and the oocyte and the importance of the cell-cell coupling pathway on glutamine action. Third, we will examine the possibility that pyruvate is a positive paracrine factor that is secreted by cumulus granulosa cells and acts on the oocyte to trigger meiotic resumption. This series of experiments will test the ability of cumulus cells and follicle hemisections to induce meiotic maturation in cocultured denuded and cumulus cell-enclosed oocytes. We will then relate this response to levels of pyruvate that accumulate in the culture medium. These results will have important implications for both fertility and contraception, since each is affected by the ability of the oocyte to successfully initiate and complete meiotic maturation. They may also help in preventing or minimizing erroneous meiotic control that can give rise to aneuploidy and its disastrous consequences. Furthermore, these studies will benefit the development of in vitro systems where either meiotic arrest or completion of meiotic maturation is the desired endpoint.
