Abstract
In iron deficiency, not only iron but lead and cadmium are hyperabsorbed. Although the mechanism controlling iron absorption is still poorly defined, it has been demonstrated that cadmium absorption proceeds via the same mechanism as iron, and cadmium and iron competitively inhibit the absorption of each other. Since cadmium, arsenic and lead are notorious for binding to sulfhydryl groups, we have explored the role of sulfhydryl groups in the regulation of iron absorption.
In the rat, administration of the sulfhydryl blocker diethyl maleate (DEM; 0.6 ml/kg i.p.) 15 minutes prior to p.o. 59Fe administration reduced iron absorption to 20% of the control value; when 59Fe was administered i.v., DEM had no effect on plasma iron clearance.
The administration of 1 mg/kg arsenic p.o. (as As2O3) dramatically inhibited the absorption of a test dose of 59Fe administered 3 hours later. Subsequent studies of mucosal glutathione metabolism indicate that GSH rapidly became bound to arsenic such that the effective GSH concentration was reduced. In response to the binding of arsenic to GSH, de novo synthesis of GSH occurred in the mucosal cell; when the GSH status returned to normal, normal iron absorption also resumed. These studies ascribe a role to GSH in iron absorption and explain why the heavy metals interfere with iron absorption.
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Pisciotto, P., Graziano, J. & Miller, D. 426 GASTROINTESTINAL IRON ABSORBTION IS SULFRYDRYL DEPENDANT: A PROPOSED MECHANISM FOR INTERFERENCE BY HEAVY METALS. Pediatr Res 12 (Suppl 4), 434 (1978). https://doi.org/10.1203/00006450-197804001-00431
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DOI: https://doi.org/10.1203/00006450-197804001-00431