Malabsorption of hemoglobin iron in pernicious anemia: correction with intrinsic factor—containing substances

Abstract

Hemoglobin iron absorption in patients with treated prenicious anemia (PA) and concomitant iron deficiency was low compared to absorption in patients with iron deficiency alone. Crude and purified hog intrinsic factor (IF) concentrates doubled the absorption of hemoglobin iron in these patients as did normal (neutralized depepsinized) human gastric juice. Hemoglobin iron absorption was not significantly enhanced by PA gastric juice. Absorption of heme iron, like that of hemoglobin iron, was enhanced by normal neutralized depepsinized gastric juice. No enhancement of hemoglobin iron absorption by these substances was obtained in the normal or iron-deficient non-PA control subjects. Preincubation of the hog IF concentrate with antisera to IF significantly reduced the enhancement of hemoglobin iron absorption due to the concentrate. In vitro studies suggest that heme complexes with a substance present in IF-containing materials. Whether a gastric glycoprotein similar to IF serves as an intestinal transport factor for heme, similar to transport of vitamin B₁₂, or whether normal gastric juice acts by another mechanism cannot be determined at this time.