title: Pu-erh tea hot-water extract activates Akt and induces insulin-independent glucose transport in rat skeletal muscle.
abstract: Skeletal muscle is a major organ that is important for whole-body glucose metabolism. We found that when isolated rat epitrochlearis muscle was incubated with a Pu-erh tea hot-water extract (PTE) for 30 min, the rate of 3-O-methyl-D-glucose (3MG) transport increased in the absence of insulin. This activation was associated with an increase in Ser(473) phosphorylation of Akt, a signaling intermediary leading to insulin-dependent glucose transport, but not Tyr(458) phosphorylation of phosphoinositide 3-kinase p85, an upstream molecule of Akt. PTE-stimulated 3MG transport was also not accompanied by Thr(172) phosphorylation of the catalytic α-subunit of 5'-AMP-activated protein kinase (AMPK). Gallic acid, a water-soluble ingredient in Pu-erh tea, stimulated Akt phosphorylation, but not AMPK phosphorylation. These results suggest that Pu-erh tea potentially promotes skeletal muscle glucose transport at least in part by activating Akt.
authors: Laboratory of Sports and Exercise Medicine, Kyoto University Graduate School of Human and Environmental Studies, Kyoto, Japan. ma.xiao.edu@gmail.com
authors: Xiao
authors: X
authors: Ma
authors: Satoshi
authors: S
authors: Tsuda
authors: Xin
authors: X
authors: Yang
authors: Ning
authors: N
authors: Gu
authors: Hiroko
authors: H
authors: Tanabe
authors: Rieko
authors: R
authors: Oshima
authors: Tetsuya
authors: T
authors: Matsushita
authors: Tatsuro
authors: T
authors: Egawa
authors: Ai-Jun
authors: AJ
authors: Dong
authors: Bei-Wei
authors: BW
authors: Zhu
authors: Tatsuya
authors: T
authors: Hayashi
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D028244:Camellia / Q000737:chemistry*; D005707:Gallic Acid / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D021122:Protein Subunits / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction; D013662:Tea
chemical_list: D000596:Amino Acids; D007328:Insulin; D010936:Plant Extracts; D021122:Protein Subunits; D013662:Tea; D005707:Gallic Acid; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D055372:AMP-Activated Protein Kinases; D005947:Glucose