Activation of 5′AMP-activated protein kinase in skeletal muscle by exercise and phytochemicals

Abstract

Skeletal muscle is the principal site of whole-body glucose, lipid, and energy me-tabolism, and several adaptive responses to physical exercise (muscle-contracting stimuli) by skeletal muscle contribute to whole-body health-promoting effects. Acute and/or repeated activation of skeletal muscle 5′AMP-activated protein kinase (AMPK) by physical exercise controls several metabolic adaptations. Thus, skeletal muscle AMPK is likely to be a " cen-tral molecule " that mediates anti-obesity/antidiabetes effects in response to physical exercise. Meanwhile, recent reports suggest that functional foods and their natural components (so-called phytochemicals) have anti-obesity/antidiabetes properties that stimulate skeletal muscle AMPK activity in a similar manner to physical exercise. For example, caffeine is a plant alkaloid that activates skeletal muscle AMPK and the activation mechanisms are exercise-like in terms of the association between α isoform-specific AMPK activation and the energy status. Further-more, berberine, a component of natural medicines, resveratrol, a polyphenol found in red wine and other plant products, and caffeic acid, a coffee polyphenol, all stimulate AMPK activation in skeletal muscle accompanied by energy deprivation. In this study, we review our recent find-ings and related studies of the activation of AMPK by physical exercise and phytochemicals.