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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been reported that the mitochondrial cytochromes and citrate cycle enzymes occur in constant proportions to each other and increase or decrease roughly in parallel in response to various stimuli. The purpose of this study was to determine whether this proportionality is an obligatory consequence of the way in which mitochondria are assembled. Severe iron deficiency was used to bring about decreases of the iron-containing constituents of the mitochondrial respiratory chain in skeletal muscle. Cytochrome c concentration and cytochrome oxidase activity were decreased approximately 50%, while succinate dehydrogenase and NADH dehydrogenase activities were decreased by 78% in iron-deficient muscle. On electron microscopic examination, mitochondria in iron-deficient muscles had relatively sparse numbers of cristae. The iron deficiency had little or no effect on the levels of a range of mitochondrial matrix enzymes, including citrate synthase, isocitrate dehydrogenase, fumarase, aspartate aminotransferase, 3-hydroxyacyl-CoA dehydrogenase, 3-ketoacid-CoA transferase, and acetoacetyl-CoA thiolase. These results show that the usual constant proportions between the constituents of the mitochondrial respiratory chain and matrix enzymes are not obligatory; they provide evidence that mitochondrial matrix enzymes and respiratory chain constituents can be incorporated into mitochondria independently and that the ratios between them can vary within wide limits.
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PMID:Perturbation of mitochondrial composition in muscle by iron deficiency. Implications regarding regulation of mitochondrial assembly. 302 53

Submitochondrial particles prepared from liver and skeletal muscle of control and iron-deficient rats were examined for cytochrome content and for both energy-independent and energy-conserving functions. Liver submitochondrial particles appear quite resistant to iron deficiency with cytochrome content and electron-transferring or energy-conserving functions maintained at a level of 85% or better of normal. Iron-deficient skeletal muscle submitochondrial particles, in contrast, have decreased cytochrome content and only 15-20% of the normal capacity for oxidation through either complex I (NADH dehydrogenase) or complex II (succinate dehydrogenase). Energy-linked reactions which involve substrate oxidation/reduction (succinate----NAD+ reversed electron flow and succinate-driven energy-dependent transhydrogenation) are likewise markedly decreased, while ATP-driven energy-dependent transhydrogenation and mitochondrial ATPase are normal. Our data support the concept that iron deficiency leads to decreased electron-carrying capacity of iron-containing mitochondrial enzymes, with skeletal muscle being much more susceptible than liver, but that the mitochondria are otherwise normal with regard to energy conservation.
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PMID:Effect of iron deficiency on energy conservation in rat liver and skeletal muscle submitochondrial particles. 405 63

Iron may affect both respiratory O2 transport and mitochondrial electron transport in the performance of muscle work. This study was designed to elucidate the molecular defect of iron-deficient work performance by identifying heretofore unmeasurable mitochondrial enzymes that are diminished by iron deficiency and may be restored by iron repletion. Female rats were made iron-deficient by dietary control and were repleted by oral iron. Iron deficiency reduced physical work capacity (treadmill running time), haemoglobin (Hb), and mitochondrial iron-sulphur (Fe-S) centres in heart and skeletal muscles; mitochondrial number was unaffected. Oral iron supplementation restored work capacity and Hb within 4 d to normal or near-normal levels, but in general Fe-S centres of mitochondria due to NADH dehydrogenase remained at iron-deficient levels. Subnormal concentrations of mitochondrial iron-dependent NADH dehydrogenase in muscle are not by themselves rate-limiting in work performance.
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PMID:Mitochondrial NADH dehydrogenase in iron-deficient and iron-repleted rat muscle: an EPR and work performance study. 629 76