ABSTRACT
This chapter discusses some nontraditional sites and mechanisms of chemical interference with hypothalamus-pituitary-gonadal function, identified in a well-characterized vertebrate model of reproductive endocrine toxicology, the Atlantic croaker. It describes toxic actions of xenobiotics in the hypophysiotropic region of the hypothalamus, at the pituitary, ovary, oocytes, and sperm, resulting in disruption of endocrine function. Xenobiotics could also potentially interfere with nongenomic actions of steroids mediated by binding to steroid membrane receptors on oocytes and sperm plasma membranes or interfere with binding of catecholestrogens to catecholamine receptors in the brain. The characteristics of maturation-inducing steroid receptors on plasma membranes of oocytes and sperm and their physiological roles in the final maturation of gametes are described. Vertebrate reproduction is an intricate process involving extensive physiological coordination, which is primarily controlled by the hormones secreted by the hypothalamus–pituitary–gonadal axis. In addition, studies showing that representative neurotoxic chemicals can impair neuroendocrine reproductive function by disrupting hypothalamic serotonergic systems are summarized.
