Figure 2.

Male muscle-specific knockout of sirtuin 1 (mKO) mice show no impairments in contractile function or fatiguability compared with wild type (WT). A and B: in WT and mKO mice, temporal force production recording during a 10-min contraction protocol (40 subsequent contractions) in the extensor digitorum longus (EDL; A) and soleus (B). In both EDL and soleus muscles, there was a main effect of time (i.e., contraction) on force production but no effect of genotype. Statistics: data were analyzed by repeated measures two-way ANOVA. *P < 0.05. C and D: fatigue index (time taken for force to decrease to 60% and 40%, of initial force) in the EDL (C) and soleus (D) of WT and mKO male mice. Statistics: data were analyzed by a repeated measures two-way ANOVA. Note: 2-deoxyglucose uptake was not measured in all muscles. Male: WT-soleus, n = 8; WT-EDL, n = 8; mKO-soleus, n = 7; mKO-EDL, n = 7. Data are presented as means ± SE.