Genetic impairment of AMPK{alpha}2 signaling does not reduce muscle glucose uptake during treadmill exercise in mice

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Some studies suggest that the 5'-AMP-activated protein kinase (AMPK) is important in regulating muscle glucose uptake in response to intense electrically stimulated contractions. However, it is unknown if AMPK regulates muscle glucose uptake during in vivo exercise. We studied this in male and female mice over-expressing kinase-dead alpha2-AMPK (AMPK-KD) in skeletal and heart muscles. Wildtype and AMPK-KD mice were exercised at the same absolute intensity and the same relative intensity (30% and 70% of individual maximal running speed) to correct for reduced exercise capacity of the AMPK-KD mouse. Muscle glucose clearance was measured using [3H]-2-deoxy-glucose as tracer. In wildtype mice glucose clearance was increased at 30% and 70% of maximal running speed by 40% and 350% in the quadriceps muscle, and by 120% and 380% in gastrocnemius muscle, respectively. Glucose clearance was not lower in AMPK-KD muscles compared to wildtype regardless of whether animals were exercised at the same relative or the same absolute intensity. In agreement, surface membrane content of the glucose transporter GLUT4 was increased similarly in AMPK-KD and wildtype muscle in response to running. We also measured signaling of alternative exercise sensitive pathways which might be compensatorily increased in AMPK-KD muscles. However, increases in phosphorylation of CaMKII, Trisk95, p38 MAPK and ERK1/2 were not higher in AMPK-KD than in WT muscle. Collectively, these findings suggest that alpha2-AMPK signaling is not essential in regulating glucose uptake in mouse skeletal muscle during treadmill exercise and that other unknown mechanisms play a central role. Key words: exercise, glucose uptake, AMPK.
TidsskriftAmerican Journal of Physiology: Endocrinology and Metabolism
Udgave nummer4
Sider (fra-til)E924-E934
Antal sider11
StatusUdgivet - 2009

Bibliografisk note

CURIS 2009 5200 103

ID: 14022859