Polychlorinated biphenyl-stimulated selenium deficiency in the chick.

Experiments were conducted to determine individually the effects of dietary PCBs on the physiologic functions of vitamin E and selenium. Results showed that dietary PCBs did not affect the function of vitamin E in protection of biological membranes. However, PCBs did decrease the biological utilization of dietary selenium as measured by glutathione peroxidase activity in plasma and by the protection of biological membranes from peroxidation. These results indicate that dietary PCBs potentiate vitamin E-selenium deficiency in the chick by interference with the biological utilization of dietary selenium. An hypothesis for the mechanism of this effect is offered.