Environmental stress and ovarian function.

The female reproductive system is exposed to a great variety of environmental stresses. These include many noxious chemicals consumed either intentionally in the form of therapeutic and recreational drugs, or unwittingly as residues in the food we eat or pollutants in the air we breathe. These stresses and noxious agents influence ovarian function through actions at a number of sites and by diverse mechanisms. Sites of action include: the hypothalamo-hypophyseal system, resulting in disruption of the normal pattern of gonadotropin secretion; the ovary, resulting in direct destruction of the oocyte (ovotoxicity) or genetic damage (mutagenicity); and other organs, leading indirectly to altered ovarian function, e.g., through metabolic alterations that change the balance of feedback control of the hypothalamo-pituitary-ovarian system. Susceptibility of the ovaries to the different classes of agents depends on the stage of development at which exposure occurs. Consequences may be temporary and reversible when the source of the "stress" is removed, or permanent if exposure occurs at a "critical stage" in ovarian or hypothalamic differentiation.