Effect of fiber type and nutritional state on AICAR- and contraction-stimulated glucose transport in rat muscle

TY - JOUR

T1 - Effect of fiber type and nutritional state on AICAR- and contraction-stimulated glucose transport in rat muscle

AU - Ai, Hua

AU - Ihlemann, Jacob

AU - Hellsten, Ylva

AU - Lauritzen, Hans P.M.M.

AU - Hardie, D. Grahame

AU - Galbo, Henrik

AU - Ploug, Thorkil

N1 - PUF 2002 5200 060

PY - 2002

Y1 - 2002

N2 - AMP-activated protein kinase (AMPK) may mediate the stimulatory effect of contraction and 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) on glucose transport in skeletal muscle. In muscles with different fiber type composition from fasted rats, AICAR increased 2-deoxyglucose transport and total AMPK activity approximately twofold in epitrochlearis (EPI), less in flexor digitorum brevis, and not at all in soleus muscles. Contraction increased both transport and AMPK activity more than AICAR did. In EPI muscles, the effects of AICAR and contractions on glucose transport were partially additive despite a lower AMPK activity with AICAR compared with contraction alone. In EPI from fed rats, glucose transport responses were smaller than what was seen in fasted rats, and AICAR did not increase transport despite an increase in AMPK activity. AICAR and contraction activated both alpha(1)- and alpha(2)-isoforms of AMPK. Expression of both isoforms varied with fiber types, and alpha(2) was highly expressed in nuclei. In conclusion, AICAR-stimulated glucose transport varies with muscle fiber type and nutritional state. AMPK is unlikely to be the sole mediator of contraction-stimulated glucose transport.

AB - AMP-activated protein kinase (AMPK) may mediate the stimulatory effect of contraction and 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) on glucose transport in skeletal muscle. In muscles with different fiber type composition from fasted rats, AICAR increased 2-deoxyglucose transport and total AMPK activity approximately twofold in epitrochlearis (EPI), less in flexor digitorum brevis, and not at all in soleus muscles. Contraction increased both transport and AMPK activity more than AICAR did. In EPI muscles, the effects of AICAR and contractions on glucose transport were partially additive despite a lower AMPK activity with AICAR compared with contraction alone. In EPI from fed rats, glucose transport responses were smaller than what was seen in fasted rats, and AICAR did not increase transport despite an increase in AMPK activity. AICAR and contraction activated both alpha(1)- and alpha(2)-isoforms of AMPK. Expression of both isoforms varied with fiber types, and alpha(2) was highly expressed in nuclei. In conclusion, AICAR-stimulated glucose transport varies with muscle fiber type and nutritional state. AMPK is unlikely to be the sole mediator of contraction-stimulated glucose transport.

U2 - 10.1152/ajpendo.00167.2001

DO - 10.1152/ajpendo.00167.2001

M3 - Journal article

SN - 0193-1849

VL - 282

SP - E1291-E1300

JO - American Journal of Physiology - Endocrinology and Metabolism

JF - American Journal of Physiology - Endocrinology and Metabolism

IS - 6

ER -