Sequence of development of iron deficiency in the rat.

This study was designed to determine the interrelationships among storage iron, transport iron, and iron compounds that serve known physiological functions (Hb, myoglobin, and cytochrome c) during the gradual progression of dietary iron deficiency. These three categories of iron compounds are generally considered to become depleted in three corresponding, sequential stages. However, there is scattered evidence of substantial overlap between these stages in man. The presence of such overlap may prove pertinent to the interpretation of laboratory tests used in the diagnosis of iron deficiency. The rat was used as an experimental model to allow more complete evaluation of the interrelationships between the stages of iron deficiency than would be possible in man. Rats were given diets containing 2, 6 and 50 mg iron/kg diet during early adult development, between 36 and 90 days of age. The iron-deficient diets (2 and 6 mg iron/kg diet) resulted in decreases in hematocrit and in muscle and intestinal cytochrome c well before storage iron in the liver and spleen was exhausted. The results in the rat model may help to explain why there is not a consistent pattern of laboratory abnormalities in individuals with chronic, mild dietary iron deficiency.