The overall goal of this project is to study the induction of the amino acid transport systems specific for the precursors of glutathione in the mouse ovarian follicle and in oocytes. Our preliminary studies show that the amino acid transport systems for the three precursors of glutathione, cystine, glycine and glutamate, are induced in preantral follicles after being cultured four hours in Waymouth medium in air containing 5% carbon dioxide [20% oxygen]. The specific aims are: (l) to identify the induced Na-independent and Na-dependent glutamate uptake systems; (2) to determine the factors required for the induction of amino acid transport systems for cystine, glycine and glutamate and the role of uptake on glutathione synthesis; (3) to test the hypothesis that ovulation and fertilization are in vivo events that result in the induction of systems x(c-) and Gly. Three factors, amino acids, oxidant stress and glutathione, will be investigated as potential candidates regulating the induction of systems x(c-), X(AG-) and Gly and glutathione levels. In amino acid supplementation experiments, preantral follicles will be cultured with selected amino acids at 3% oxygen to minimize oxidant stress. When follicles are cultured with different levels of oxygen, superoxide anion and hydrogen peroxide, Waymouth medium will be supplemented with the amino acids needed for glutathione synthesis. When varying glutathione levels, follicles will be cultured at 3% oxygen and in amino acid supplemented medium. Timing of the in vivo expression of systems x(c-) and Gly and glutathione levels will be determined in ovulated-unfertilized and fertilized oocytes. These studies may benefit work involving in vitro culture of immature oocytes and fertilization of mature oocytes in agriculturally important species.