Plasma citrate during submaximal and intermittent supramaximal exercise.
Plasma citrate was determined in seven subjects working 45 min at 50-60% of their maximal aerobic power and in six subjects who were exercised intermittently for five periods of 1 min at supramaximal work loads. Determinations of plasma lactate, glucose, free fatty acids and insulin were carried out simultaneously. During submaximal work the mean plasma citrate concentration decreased from 116 +/- 4 mumol/1 at rest to 108 +/- 5 mumol/1 after 10 min exercise (P less than 0.05) and increased above resting level to 136 +/- 5 mumol/1 40 min after cessation of work (P less than 0.05). During intermittent supramaximal exercise, mean plasma citrate concentration rose after the third work period and during recovery from 117 +/- 6 mumol/1 at rest to 181 +/- 9 mumol/1 40 min after last work period (P less than 0.05). Plasma citrate varied similarly to variations in plasma free fatty acids and inversely to changes of lactate concentrations during submaximal exercise. Opposite interrelationships were demonstrated during intermittent supramaximal exercise. Plasma citrate concentration varied in the same way as might be expected for changes in cytosolic citrate levels of muscle from in vitro knowledge of the regulatory role of citrate on glucose oxidation.
D000328:Adult; D002951:Citrates / Q000097:blood*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D005082:Physical Exertion; D013997:Time Factors
D002951:Citrates; D005230:Fatty Acids, Nonesterified; D007773:Lactates