Endocrine Disruptors; Possible Mechanisms for Inducing Developmental Disorders

Dear Editor, Polychlorinated aromatic hydrocarbons (PAHs) include polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins (PCDDs).1-5 These endocrine-disrupting compounds (EDCs) are stored in animal and human tissues6-9 causing a hormonal disturbance2,3,10 and developmental defects.11 In addition, they have the ability to cross the placenta producing several toxic effects on the placental tissue,12-14 and fetal/neonatal development.8,15-18 These toxic effects might be associated with variations in thyroid functions19,20 which are necessary throughout the regular development.21-56 Administration of PCB 95 at 32 mg/kg/d to newborn rats caused hypothyroidism and thyroid dysgenesis (DNA fragmentation) at postnatal day 18.28 Furthermore, hypothyroidism was observed in children living near PCB-contaminated sites.