Oxygen electrode studies with human skeletal muscle mitochondria in vitro. A re-appraisal.
Polarographic measurement of respiration rates in skeletal muscle mitochondria is a valuable research tool in human disease but the data on normal muscle are sparse and conflicting. In this study, mitochondria were isolated from 18 normal muscle biopsies and state 3 respiration rates measured with glutamate/malate, pyruvate/malate and succinate as substrates. In 13 experiments, reproducible respiration rates with adequate respiratory control ratios (RCR) and ADP/O ratios were obtained. Mean state 3 respiration rates of 280 ng-atoms 0 min-1 mg mitochondrial protein-1 (30 degrees C) with glutamate, 214 ng-atoms 0 min-1 mg mitochondrial protein-1 (30 degrees C) with pyruvate and 353 ng-atoms 0 min-1 mg mitochondrial protein-1 (30 degrees C) with succinate as substrates were higher than in most earlier reports. Selective uncoupling with alpha-glycerophosphate and data suggesting a partial site I deficiency were found in some experiments where RCR and ADP/O ratio measurements indicated a good preparation. Slow rates with all substrates with loose coupling were found in 3 studies where the mitochondria were clearly damaged during extraction. Guidelines for the evaluation of polarographic data in reports in the literature are suggested.
Byrne
E
E
Trounce
I
I
D000244:Adenosine Diphosphate / Q000378:metabolism; D000293:Adolescent; D000368:Aged; D002458:Cell Fractionation / Q000379:methods; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D008931:Mitochondria, Muscle / Q000378:metabolism*; D009124:Muscle Proteins / Q000494:pharmacology; D010101:Oxygen Consumption; D011048:Polarography; D011773:Pyruvates / Q000378:metabolism; D019289:Pyruvic Acid; D013386:Succinates / Q000378:metabolism; D019802:Succinic Acid; D013772:Tetramethylphenylenediamine / Q000494:pharmacology
D005971:Glutamates; D009124:Muscle Proteins; D011773:Pyruvates; D013386:Succinates; D018698:Glutamic Acid; D000244:Adenosine Diphosphate; D019289:Pyruvic Acid; D019802:Succinic Acid; D013772:Tetramethylphenylenediamine