Stimulation of iron absorption by polychlorinated aromatic hydrocarbons

Oral and intraperitoneal treatment of rats with a single dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 33 microgram/kg, causes a 41--67% increase in iron adsorption in vivo. The major effect is on the transfer of iron from the mucosa into the bloodstream rather than on the uptake of iron from the lumen of the gut. These results are confirmed in studies with everted gut sacs. The effect is maximal at 1--2 days with a dose of 22-42 microgram/kg. Calcium transport is inhibited by TCDD treatment, whereas galactose and proline transport are unaffected. Treatment of rats with 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane also stimulates iron transport. Concomitant with iron transport stimulation, aryl hydrocarbon hydroxylase activity in the intestine and liver is increased by TCDD treatment. These studies suggest that polychlorinated aromatic hydrocarbons, which are environmental health hazards, may effect the intestinal absorption of essential mineral nutrients.