ERYTHROCYTE INCORPORATION AND ABSORPTION OF FE-58 IN PREMATURE-INFANTS TREATED WITH ERYTHROPOIETIN

We hypothesized that treatment of very low birth weight premature infa nts with r-HuEPO would increase erythrocyte incorporation and, gastroi ntestinal absorption of iron. Infants with birth weights less than or equal to 1.25 kg and gestational ages <31 wk were randomized to receiv e 6 wk of 500 U of r-HuEPO/kg/wk (epo group, n = 7) or placebo (placeb o, group, n = 7). All infants received daily enteral supplementation w ith 6 mg of elemental iron per kg. An enteral test dose of a stable ir on isotope, Fe-58, was administered after the Ist (''early dosing'') a nd 4th (''late dosing'') wk of treatment. Mean (+/-SD) erythrocyte inc orporation of the dose of Fe-58 administered determined 2 wk after ear ly dosing was significantly greater in the epo group compared with the placebo group (4.4% +/- 1.6 versus 2.0 +/- 1.4%, p = 0.013). In contr ast, after late Fe-58 dosing, there was no difference between groups i n incorporation (3.8 +/- 1.6% versus 5.5 +/- 2.7%), Within the epo gro up, percentage erythrocyte incorporation of Fe-58 did not differ betwe en early and late dosing, whereas in the placebo group it increased 3- fold (p < 0.01). Percentage absorption of Fe-58 was not different betw een the epo and placebo groups after both early dosing (30 +/- 22% ver sus 34 +/- 8%) and late dosing (32 +/- 9% versus 31 +/- 6%), Absorptio n of nonlabeled elemental iron and Fe-58 were significantly correlated with one another. The percentage of the absorbed Fe-58 dose incorpora ted into Hb was not different between groups, We conclude that, althou gh erythropoietin treatment stimulates erythrocyte iron incorporation in premature infants, it has no effect on iron absorption at the r-HuE PO dose studied.