[Occupational agents and endocrine function: an update of the experimental and human evidence]

Many environmental and occupational agents have been shown to cause detrimental effects on endocrine function and growing scientific evidence supports the hypothesis that such alterations may produce serious consequences for health. Although those chemicals mimicking (or contrasting) estrogenic or androgenic actions have raised great concern, the relevance of disruption of other hormonal pathways is not negligible. This article reviews the effects of chemical and physical agents on the hypothalamus-pituitary unit, pineal gland, thyroid, parathyroid and calcium metabolism, adrenal glands, and glucose metabolism. Metals (Pb, Mn, Cd, organotin compounds), solvents (benzene, dioxane, styrene, tetrachloroethylene, toluene), organochlorines (PCBs, TCDD), and physical agents have been shown in human, animal or in vitro studies to cause alterations of the blood levels, and of the activity or circadian rhythm of pituitary hormones. Melatonin has been proposed as the link between environmental/occupational factors and the immunologic and neoplastic diseases, which in addition to disturbances of the circadian timing system, feature pineal hormone reduction. Thyroid gland diseases (goiter, autoimmune thyroiditis, carcinoma) are associated with exposure to many chemical or physical agents. Disruptions of calcium control secondary to metal exposures, as well as the effect of radiation on parathyroid, are addressed. Adrenal cortex and medulla function alterations by several chemical agents are considered. Finally, diabetes mellitus as an outcome of occupational or environmental exposures and as susceptibility to occupational and environmental factors is discussed.