The purpose of this study was to determine the effects of a single period of swim exercise to exhaustion on the cellular distribution of hexokinase in rat skeletal muscle. The gastrocnemius muscle from male rats exercised (n = 16) to exhaustion or allowed to remain inactive (n = 14) was analyzed for hexokinase activity (HK) in the whole muscle homogenate and the mitochondrial-rich fraction. Although exercise produced a slight, non-significant, increase in HK activity in the whole muscle homogenate (p < 0.09), HK activity in the mitochondrial-rich fraction was significantly increased in the exercised muscle (p < 0.02). This shift in the cellular distribution of HK is towards the more active mitochondrial bound form and indicates an enhanced regulation of HK activity during physical exercise.
Hexokinase - skeletal muscle - mitochondria - exercise
