Duodenal ferritin synthesis during iron absorption in the iron-deficient rat.

Abstract

Abstract It has been proposed that is the regulator of iron absorption and that the intestine absorbs more iron in iron deficiency because it lacks ferritin apparatus. We have tested this hypothesis by measuring the incorporation of C 14 -dl-leucine into isolated immunologically from duodenal homogenates of iron-deficient and replete rats before and 1, 3, and 5 hours after intraduodenal administration of 1 mg. of iron. The homogenates of iron-deficient rats contained little or no before intraluminal administration of iron. However, in response to iron, the duodenum of iron-deficient rats synthesized as much protein as that of iron-replete rats, and by 5 hours homogenates of iron-deficient rats contained more than did those of iron-replete rats before administration of iron. The finding that intraluminal administration of iron to the iron-deficient rat induces the synthesis of duodenal differs from the observations of other workers who quantitated by measurement of its iron and not the protein moiety. In order to explore the role of newly synthesized in iron absorption, we gave a second dose of iron to iron-deficient rats. Although absorption was reduced from 25 per cent for the first dose to 14 per cent for the second, only 0.5 per cent was found in duodenal ferritin. The absorption was still far greater than that of iron-replete rats (1.6 per cent), although the duodenal content was similar because of the stimulating effect of the first iron dose on synthesis. Our findings argue against the importance of as a regulator of iron absorption.