Effect of experimental hypoxia on the ubiquinone level of skeletal muscle in rabbits.

Rabbits were kept for 2 and 4 hours in a chamber containing a gas mixture of 92% N2 and 8% O2. The ubiquinone level in the musculus quadriceps femoris of the animals was determined. Rabbits after 4 hours hypoxia were retaken into normal conditions for 2 hours before killing. Biochemical findings revealed a significant decrease in the ubiquinone activity during hypoxia independently from duration of hypoxia. 2 hours after hypoxia the ubiquinone activity became normal. The slight alterations biochemically determined can not be followed unambiguously by histochemical methods, but the microscopic studies have revealed that the red fibres of mixed musculus quadriceps femoris are responsible for the quantitative changes.