Lead and iron absorption from rat small intestine: the effect of dietary Fe deficiency

Abstract

1. When lead is administered in drinking-water iron-deficient rats retain more Pb than Fe-replete rats (Six & Goyer, 1972; Klauder & Petering, 1975). In the present study the relationship between the absorption of Pb and Fe was investigated.2. Adult male rats were transferred to a milk-based diet fed with or without supplementary Fe (180 mg Fe/kg as ferrous sulphate). After 7–9 d the absorption of duodenally-administered203Pb and59Fe was measured as uptake of radioactivity from the gastrointestinal tract after 90 min.59Fe absorption was increased in rats given the unsupplemented diet for 7 d and was further increased in rats kept on the diet for up to 7 weeks.203Pb absorption was not consistently increased by either short- or long-term Fe deprivation.3. Much of the203Pb in homogenates of the upper small intestine was bound to soluble protein of which up to 85% was dialysable. In contrast little59Fe was dialysable. Only a small proportion of the soluble musosal Pb was associated with ferritin during gel-filtration chromatography although203Pb precipitated together with carrier rat-liver ferritin with an antibody to rat-liver ferritin.4. There appeared to be no direct relationship between the transfer of Fe and Pb across the small intestine of the adult rat.