DISTRIBUTION OF CYTOCHROME C AND MYOGLOBIN IN RATS WITH DIETARY IRON DEFICIENCY

Abstract

A decrease in cytochrome c and myoglobin concentrations was observed in young rats made anemic on a low-iron diet. The degree of depletion of hemeprotein varied according to tissue. In the iron-deficient rat, myoglobin and cytochrome c were most depleted in skeletal muscle which contains the major portion of these proteins. Cytochrome c expressed as percentage of corresponding control mean concentrations was 44% in skeletal muscle, 61% in intestinal mucosa, 69% in kidney, 79% in diaphragm, 89% in heart, and 97% in brain. Myoglobin in the iron-deficient rats was 44% of the corresponding control concentration in skeletal muscle, 63% in diaphragmatic muscle, and 80% in heart muscle. The variations in degree of hemeprotein depletion in response to iron deprivation appeared to be related to organ function, growth rate, and cell turnover. Cardiac and diaphragmatic muscle, whose function is essential to survival, resisted the loss of myoglobin and cytochrome c to a greater extent than did skeletal muscle. Severe depletion of hemeprotein was observed in tissues with a rapid rate of growth such as skeletal muscle or a rapid cell turnover as in the case of intestinal mucosa. Brain, which grows minimally during the period of iron deprivation, was unchanged in its cytochrome c content. A significant impairment of oxidative metabolism in the iron deficient rat was suggested by a reduction in the rate of respiration of muscle homogenates.