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PGC‐1α mediates a rapid, exercise‐induced downregulation of glycogenolysis in rat skeletal muscle
Author(s) -
Kim Sang Hyun,
Koh Jin Ho,
Higashida Kazuhiko,
Jung Su Ryun,
Holloszy John O.,
Han DongHo
Publication year - 2014
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2014.283820
Subject(s) - glycogenolysis , glycogen , lactic acid , downregulation and upregulation , cellular adaptation , skeletal muscle , medicine , glycolysis , endurance training , endocrinology , physical exercise , mitochondrion , chemistry , exercise physiology , biology , metabolism , biochemistry , gene , genetics , bacteria
Key points Long‐term endurance exercise training results in a reduction in the rates of muscle glycogen depletion and lactic acid accumulation during submaximal exercise; this adaptation is mediated by an increase in muscle mitochondria. There is evidence suggesting that short‐term training induces adaptations that downregulate glycogenolysis before there is an increase in functional mitochondria. We discovered that a single long bout of exercise induces decreases in expression of glycogenolytic and glycolytic enzymes in rat skeletal muscle; this adaptation results in slower rates of glycogenolysis and lactic acid accumulation in muscle during contractile activity. Two additional days of training amplified the adaptive response, which appears to be mediated by PGC‐1α; this adaptation is biologically significant, because glycogen depletion and lactic acid accumulation are major causes of muscle fatigue.Abstract Endurance exercise training can increase the ability to perform prolonged strenuous exercise. The major adaptation responsible for this increase in endurance is an increase in muscle mitochondria. This adaptation occurs too slowly to provide a survival advantage when there is a sudden change in environment that necessitates prolonged exercise. In the present study, we discovered another, more rapid adaptation, a downregulation of expression of the glycogenolytic and glycolytic enzymes in muscle that mediates a slowing of muscle glycogen depletion and lactic acid accumulation. This adaptation, which appears to be mediated by PGC‐1α, occurs in response to a single exercise bout and is further enhanced by two additional daily exercise bouts. It is biologically significant, because glycogen depletion and lactic acid accumulation are two of the major causes of muscle fatigue and exhaustion.