Rac1 in muscle is dispensable for improved insulin action after exercise in mice

TY - JOUR

T1 - Rac1 in muscle is dispensable for improved insulin action after exercise in mice

AU - Sylow, Lykke

AU - Møller, Lisbeth Liliendal Valbjørn

AU - D'Hulst, Gommaar

AU - Schjerling, Peter

AU - Jensen, Thomas Elbenhardt

AU - Richter, Erik

N1 - CURIS 2016 NEXS 158

PY - 2016/8

Y1 - 2016/8

N2 - Exercise has a potent insulin-sensitivity enhancing effect on skeletal muscle, but the intracellular mechanisms that mediate this effect are not well understood. In muscle, Ras-related C3 botulinum toxin substrate 1 (Rac1) regulates both insulin- and contraction-stimulated glucose transport and is dysregulated in insulin resistant muscle. However, whether Rac1 is involved in mediating enhanced insulin sensitivity after an acute bout of exercise is unresolved. To address this question, we investigated after exercise whole-body (insulin tolerance test) as well as muscle (insulin-stimulated 2-deoxyglucose transport in isolated soleus muscle) insulin sensitivity in inducible muscle-specific Rac1 knockout (mKO) and wild-type (WT) littermate mice. Previous exercise enhanced whole-body insulin sensitivity by 40% in WT mice and rescued the insulin intolerance in Rac1 mKO mice by improving whole-body insulin sensitivity by 230%. In agreement, previous exercise significantly improved insulin sensitivity by 20% in WT and by 40% in Rac1 mKO soleus muscles. These findings suggest that muscle Rac1 is dispensable for the insulin sensitizing effect of exercise.

AB - Exercise has a potent insulin-sensitivity enhancing effect on skeletal muscle, but the intracellular mechanisms that mediate this effect are not well understood. In muscle, Ras-related C3 botulinum toxin substrate 1 (Rac1) regulates both insulin- and contraction-stimulated glucose transport and is dysregulated in insulin resistant muscle. However, whether Rac1 is involved in mediating enhanced insulin sensitivity after an acute bout of exercise is unresolved. To address this question, we investigated after exercise whole-body (insulin tolerance test) as well as muscle (insulin-stimulated 2-deoxyglucose transport in isolated soleus muscle) insulin sensitivity in inducible muscle-specific Rac1 knockout (mKO) and wild-type (WT) littermate mice. Previous exercise enhanced whole-body insulin sensitivity by 40% in WT mice and rescued the insulin intolerance in Rac1 mKO mice by improving whole-body insulin sensitivity by 230%. In agreement, previous exercise significantly improved insulin sensitivity by 20% in WT and by 40% in Rac1 mKO soleus muscles. These findings suggest that muscle Rac1 is dispensable for the insulin sensitizing effect of exercise.

U2 - 10.1210/en.2016-1220

DO - 10.1210/en.2016-1220

M3 - Journal article

C2 - 27285860

SN - 0013-7227

VL - 157

SP - 3009

EP - 3015

JO - Endocrinology

JF - Endocrinology

IS - 8

ER -