Samples of muscle extracted before reaching high altitude and after returning to sea-level showed that maximal activities of enzymes, such as those representative of beta-oxidation, were unchanged. However, after exposure to extremely high altitude hypoxic conditions, reductions were observed in succinic dehydrogenase, citrate synthetase and hexokinase. The findings of this study did not support the researchers' hypothesis that extremely hypoxic conditions elicit changes that are adaptive toward maximizing oxidative function at the intracellular level (Green et al., 1989).
Reference
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