Oxidative Stress and the Ovary

Abstract

Superoxide (O2-), hydrogen preoxide (H2O2), and lipid peroxides are generated in luteal tissue during natural and prostaglandin-induced regression in the rat, and this response is associated with reversible depletion of ascorbic acid. Reactive oxygen species immediately uncouple the luteinizing hormone receptor from adenylate cyclase and inhibit steroideogenesis by interrupting transmitochondrial cholesterol transport. The cellular origin of oxygen radicls in regressing corpora lutea is predominately from resident and infiltrated leukocytes, notably neutrophils. Reactive oxygen species are also produced within the follicle at ovulation and, like the corpus luteum, leukocytes are the major source of the products. Antioxidants block the resumption of meiosis, whereas the generation of reactive oxygen induces oocyte maturation in the follicle. Although oxygen radicals may serve important physiologic roles within the ovary, the cyclic production of these damaging agents over years may lead to an increased cumulative risk of ovarian pathology that would probably be exacerbated under conditions of reduced antioxidant status.