The effect of pyridoxine deficiency on the absorption of iron by the rat.

The factors which govern the absorption of iron are not well understood. The current theory of iron absorption assigns to bodily need for iron the chief role in the regulation of iron absorption (1, 2). Conclusive evidence is needed, however, to demonstrate the correctness of such a view. In an earlier study from this laboratory (3), it was demonstrated that the high serum iron values and hemosiderosis of the liver and spleen, which are characteristic of pyridoxine deficiency in swine, do not appear when the experimental animals are fed a diet very low in iron content, even though all other manifestations of pyridoxine deficiency develop. This observation indicates that, at least in pyridoxine-deficient swine, iron continues to be absorbed even though it cannot be utilized and in spite of the fact that the body stores are replete with iron. Although it is evident that iron absorption in pyridoxine deficiency may represent unusual circumstances which are of no significance in the normal animal or in other types of deficiency, it was thought important to study the problem further. One point needing elucidation is whether or not iron absorption is normal, reduced, or even possibly increased in the face of pyridoxine deficiency as compared with normal. Since the answer to this question could only be obtained by smeasuring the total iron content of experimental animals, and since this could not be done easily in swine, the rat was chosen for the experimental studies to be described. The rat differs from swine and dogs in that little or no anemia develops when pyridoxine deficiency is produced, even though various other signs of this deficiency do (4, 5).