Skip to main content
. 2013 Oct 23;3(1):29–41. doi: 10.1016/j.molmet.2013.10.005

Figure 5.

Figure 5

Altered glucose metabolism in skeletal muscles from Bmal1 mKO mice. (A) Glucose oxidation to CO2 measured in isolated diaphragms incubated with 5 mM [1-14C]-glucose at ZT12, at the light/dark transition (mean±SEM; n=5–10/group; *p<0.05, **p<0.01, Student's t-test). (B)–(D) Active pyruvate dehydrogenase (PDHa) activity and PDH phosphorylation in gastrocnemius muscles from Ctrl and mKO mice. (B) Diurnal pattern of PDHa activity. Data are expressed as mmoles/min/kg wet weight (mean±SEM; n=3/group/timepoint; 2-way ANOVA group effect F=6.66, p=0.016). Right panel shows mean 24-h PDHa activity in muscles from Ctrl and mKO mice (mean percent relative to control±SEM; n=18/group; *p<0.05, Student's t-test). (C) Mean 24-h PDHa activity in muscles from Ctrl (n=13) and imKO mice (n=16) (mean percent relative to control±SEM; *p<0.05, Student's t-test). (D) Diurnal PDH-E1α Ser300 phosphorylation quantified by densitometry after western blot analysis in muscles across the diurnal cycle (normalized to total PDH-E1α protein; mean±SEM; arbitrary units; n=3/group/timepoint; 2-way ANOVA group effect F=6.58, p=0.0173). Right panel shows mean 24-h PDH-E1α Ser300 phosphorylation in mKO and control muscles (mean±SEM; arbitrary units; n=18/group; **p<0.01, Student's t-test). (E) Diurnal gene expression profiles of PDH kinase 4 (Pdk4) in Ctrl and mKO TA and SOL muscles detected by qPCR and plotted relative to 36B4 expression (mean±SEM; n=3/group/timepoint; *p<0.05, 2-way ANOVA with the Bonferroni correction). (F) PDK4 protein levels in Ctrl and mKO muscles (gastrocnemius) immediately before and during the dark/active phase (average of values measured at ZT8, 12, 16 and 20) (mean±SEM; n=12; *p<0.05, Student's t-test). (G) Diurnal gene expression profiles of PDH phosphatase 1 (Pdp1) in Ctrl and mKO TA and SOL muscles detected by qPCR and plotted relative to 36B4 expression (mean±SEM; n=3/group/timepoint; *p<0.05, **p<0.01, ***p<0.001, 2-way ANOVA with the Bonferroni correction). (H) Western blots showing PDP1 protein levels, as measured immediately before and during the dark/active phase, in mKO and Ctrl gastrocnemius muscles. (I) PDP1 protein levels in mKO and Ctrl muscles (gastrocnemius) immediately before and during the dark/active phase (ZT8-20; mean±SEM; arbitrary units; n=4/group; **p<0.01, Student's t-test).