Ontogeny of ovarian glutathione and sensitivity to primordial oocyte destruction by cyclophosphamide

Ovarian reduced glutathione concentration (microgram/mg wet ovarian weight) develops from levels of less than 0.2 microgram/mg in newborn Osborn Mendel rats to plateau at 0.7 microgram/mg between the ages of 3-7 weeks of age, finally reaching mature levels of approximately 1.0 microgram/mg between 7-8 weeks of age. Ovarian reduced glutathione concentration matures somewhat faster in Sprague Dawley rats, reaching mature levels of 1.0 microgram/mg between 4-6 weeks of age. The development of ovarian glutathione from immature (less than 0.2 microgram/mg) to mature levels (1.0 microgram/mg) was also observed over similar developmental time spans in DBA/2N and C57BL/6N mice. The sensitivity of primordial oocytes to destruction by cyclophosphamide in C57BL/6N mice was considerably different at 4 and 6 weeks of age. The ED50 for primordial oocyte destruction at 4 weeks of age in C57BL/6N mice was 140 mg/kg while at 6 weeks of age the ED50 was 260 mg/kg. The increase in ovarian reduced glutathione with age and the increasing resistance to primordial oocyte destruction over the same time period are consistent with the hypothesis that glutathione plays a major role in the modulation of primordial oocyte destruction.