Glycogen repletion in different types of muscle and in liver after exhausting exercise.

I’ERJUNG, R. L., K. M. BALIX~~N, W. W. WINDER, AND J. Q. HOLLOSZY. GLycogen repletion in cli$erent types of muscle and in Iiver ufter exhausting exercise. Am. J. Physiol. 226(6): 1387-1391. 1974.Glycogen repletion rates in fast-twitch red, slow-twitch red, and fast-twitch white types of skeletal muscle, in heart, and in liver were compared in rats after depletion of glycogen stores by exercise. ‘rhe highest rates of glycogen synthesis in all five tissues were seen between 30 and 60 min after exercise. The fastest glycogen synthesis rate in the three types of skeletal muscle was seen in fast-red muscle which had a peak synthesis rate 3 times as great as white and twice as great as slow-red muscle. Heart muscle had a glycogen synthesis rate 125y0 that of fast-red muscle. Liver had a synthesis rate 17570 that of fast-red muscle. Glycogen concentrations are much higher in liver than in muscle in fed, rested rats; therefore, although liver had the fastest glycogen synthesis rate, glycogen attained control levels later in liver than in the muscles.