Effect of enhanced erythropoiesis on iron absorption.
To examine the influence of erythropoiesis on iron absorption, radioiron absorption tests were performed in normal subjects before and after a course of recombinant erythropoietin. The absorption of heme and nonheme iron from a standard meal was measured in nine subjects, and the absorption of a therapeutic dose of ferrous sulfate given with or without food was determined in an additional 11 subjects. The subcutaneous administration of 100 U recombinant human erythropoietin/kg body weight given on 10 successive days over a 2-week period induced a brisk increase in erythropoiesis and a sharp decrease in iron stores. With the standard meal, there was a modest increase in heme iron absorption from 47.0% to 58.6% (p < 0.05) and a dramatic five-fold rise in nonheme iron absorption from 5.9% to 31.8% (p < 0.001). The absorption of 50 mg iron as ferrous sulfate increased from 2.0% to 17.9% when given with food (p < 0.001) and from 7.0% to 24.6% when given with water (p < 0.001). To assess the effect of erythropoiesis independently of the induced changes in iron status, the absorption data were adjusted to a common serum ferritin level. The relative increase in iron absorption was still significant for both dietary nonheme iron (ratio 2.51, p < 0.02) and ferrous sulfate given with food (ratio 2.99, p < 0.01). It is concluded that the striking enhancement of iron absorption following regular erythropoietin administration in normal subjects is related to the combined effect of diminished iron stores and augmented erythropoiesis.
Skikne
B S
BS
Department of Medicine, Kansas University Medical Center, Kansas City 66160-7402.
Cook
J D
JD
D000328:Adult; D004920:Erythropoiesis / Q000502:physiology*; D004921:Erythropoietin / Q000494:pharmacology*; D005260:Female; D005293:Ferritins / Q000097:blood; D005296:Ferrous Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics; D005502:Food; D006418:Heme / Q000378:metabolism; D006801:Humans; D007408:Intestinal Absorption; D007501:Iron / Q000097:blood / Q000378:metabolism*; D007504:Iron Radioisotopes; D008297:Male; D011994:Recombinant Proteins / Q000494:pharmacology; D014168:Transferrin / Q000378:metabolism
D005296:Ferrous Compounds; D007504:Iron Radioisotopes; D011994:Recombinant Proteins; D014168:Transferrin; D004921:Erythropoietin; C020748:ferrous sulfate; D006418:Heme; D005293:Ferritins; D007501:Iron