Experimental and clinical studies on the reproductive toxicology of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin

The reproductive toxicology of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) has been studied in animal models and in human populations. In animals, TCDD has a range of toxic effects on organs of the reproductive system in males and females, on hormone biochemistry, and on embryo‐fetal development. These effects may involve in part an identified intracellular TCDD receptor and its association with the induction of microsomal cytochrome P‐450‐dependent monooxygenases in many organs. TCDD treatment increases activity of monooxygenase enzyme in liver and gonads of treated animals, but unlike other polycyclic aromatic hydrocarbons that are monooxygenase inducers, TCDD is not cytotoxic to any population of oocytes in the mature female mouse. Epidemiological studies of TCDD reproductive toxicity have been limited in design. There are some reports of adverse effects in the Seveso population and in children born to American veterans presumed to have been exposed to TCDD in Agent Orange during the Vietnam war. Occupational cohorts have not been found to show such paternally mediated effects of TCDD exposure.