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- Title
Regulation of Glycogen Synthase Kinase-3 in Human Skeletal Muscle.
- Authors
Wojtazsewski, Jørgen F. P.; Nielsen, Pernille; Klens, Bente; Richter, Erik A.
- Abstract
Studies of skeletal muscle from rodents performed both in vivo and in vitro suggest a regulatory role of glycogen synthase kinase (GSK) 3 in glycogen synthase (GS) activation in response to insulin. Recently, hyper-insulinemic clamp studies in humans support such a role under nearly physiological conditions. In addition, in rats the activation of GS in skeletal muscle during treadmill running is time-related to the deactivation of GSK3. We investigated whether GSK3 was deactivated in human muscle during low- (~5O% Vo[sub 2max]for 1.5 h) and high-intensity (~75% Vo[sub 2max]for 1 h) bicycle exercise as well as food intake. We observed a small but significant increase in GSK3a (10-20%) activity in biopsies obtained from vastus lateralis after both low-and high-intensity exercise, whereas GSK3Β activity was unaffected. Subsequent food intake increased Akt-phosphorylation (~2-fold) and deactivated GSK3a (~40%), whereas GSK3Β activity was unchanged. GS activity increased in response to both exercise and food intake. We conclude that GSK3a but not GSK3Β may have a role in the regulation of GS activity in response to meal-associated hyperinsulinemia in humans. However, in contrast to findings in muscle from rats, exercise does not deactivate GSK3 in humans, suggesting a GSK3-independent mechanism in the regulation of GS activity in muscle during physical activity. Diabetes 50:265-269, 2001
- Subjects
GLYCOGEN synthase kinase-3; SKELETAL muscle; INSULIN; STRIATED muscle; GLYCOGEN synthase kinase
- Publication
Diabetes, 2001, Vol 50, Issue 2, p265
- ISSN
0012-1797
- Publication type
Article