Is Erythropoietic Action of Copper Dependent upon Presence of Adequate Supply of Iron in Diet? ∗

Abstract

In studying the effect of evaporated milk upon the development of nutritional anemia in the albino rat, it was observed that the erythrocytes were maintained at a normal level over a period of 8 weeks in spite of the fact that the hemoglobin fell slowly. This was in sharp contrast to the findings on rats which were fed raw milk, where both the erythrocyte count and the hemoglobin showed a marked decrease in 7 1/2 weeks.

In the majority of evaporated milk plants the milk comes in close contact with copper during the manufacturing process. Since according to Rice and Miscall 1 copper is dissolved by milk under such conditions, an investigation has been undertaken to determine if this metal is the causative factor in the maintenance of the red cell count when evaporated milk is fed.

Albino rats, 21 days of age, were fed raw milk supplemented by 0.025 mg. of copper (as CuSO₄) daily over a period of 8 weeks. Erythrocyte counts and hemoglobin determinations were made at the beginning of the experiment and at intervals of 2 weeks thereafter. The experimental data obtained, with those from rats on raw milk alone and on evaporated milk without supplement, are given in Table I.

One may conclude that the maintenance of a normal erythrocyte count for 8 weeks when evaporated milk is fed as the sole article of diet is due in part at least to the copper content of the evaporated milk, as a similar though less marked effect is obtained when raw milk is supplemented with copper.

The recent report of Schultze 2 that, even when the diet is poor in iron, copper fed to young anemic rats has an erythropoietic action without stimulating hemoglobin regeneration is supported by our experimental findings.