Corpus luteum: animal models of possible relevance to reproductive toxicology

The presence of a normally functioning corpus luteum is an essential requirement for the maintenance of gestation in mammals. The chief function of the corpus luteum in all species is to synthesize the steroid hormone progesterone that is necessary for implantation and for the subsequent development of the fetoplacental unit. Activation and maintenance of luteal function involve pituitary, placental, and ovarian hormones. Perturbation in the secretion and/or action of any of these luteotropins by exogenous compounds can profoundly affect the steroidogenic capacity of the corpus luteum. Abnormal luteal function causes failure of implantation and embryonic wastage. Both in vitro and in vivo models for assessing luteal function are available; while the former are more convenient, the model of choice for toxicological studies is one in which in vitro findings can be easily confirmed in whole animals in vivo. This article is concerned primarily with the techniques used in basic research that might be useful for the evaluation of luteal function in reproductive toxicology.