IRON-DEFICIENCY ANEMIA - MITOCHONDRIAL ALPHA-GLYCEROPHOSPHATE DEHYDROGENASE IN GUINEA-PIG SKELETAL-MUSCLE

  • 1 January 1985
    • journal article
    • research article
    • Vol. 105  (1) , 11-18
Abstract
Severe Fe deficiency anemia in rats causes a decrease in the activities of Fe-containing enzymes in skeletal muscle mitochondria and subsequent diminished respiratory activity was linked to lowered work capacity. Loss of mitochondrial .alpha.-glycerophosphate dehydrogenase activity may play a particularly important role in this process and, by inference, in the clinical manifestations of Fe deficiency anemia. This view may be ill founded, inasmuch as other pathways with potentially greater activity are capable of transporting reducing equivalents from the cytosol into the mitochondria in mammalian skeletal muscle. Fe deficiency anemia of a severity on the order of that in humans was produced in guinea pigs. Mitochondria from skeletal muscles of test animals exhibited respiration rates diminished by 24-36% compared with control mitochondria in the presence of several substrates. Differences in respiration were not observed with .alpha.-glycerophosphate as substrate, nor were there differences in .alpha.-glycerophosphate dehydrogenase enzyme activity between mitochondria from Fe-deficient and control animals. Although cytochrome oxidase activity and muscle mitochondrial protein content were the same in both groups of guinea pigs, cytochrome and flavoprotein concentrations were lower in mitochondria from Fe-deficient animals and there was a preferential loss of cytochrome c + c1. Fe deficiency anemia in guinea pigs thus results in impaired oxygen metabolism in skeletal muscle mitochondria that is associated with a general decrease in the concentrations of Fe-containing electron transport chain components as well as with an alteration in chain stoichiometry. Mitochondrial .alpha.-glycerophosphate dehydrogenase does not appear to play a role in this process.