Table 1.
Body composition and metabolic characterization.
Figure 1.
Characterization of whole body glucose homeostasis.
(A) OGGT (2 g/kg body weight) and C) ITT (0.5 U/kg body weight) were conducted after 5 hours of fasting. Values are expressed as AUC based on weighted means of all glucose measurements (t = −15, 20, 40, 60, 90 and 120 min). Figure 1B shows plasma insulin concentrations before (0 min) and after 20 min in response to the OGTT. Figure 1D illustrates calculated HOMA-IR index values based on basal glucose and insulin concentrations obtained after 5 hour of fasting. Measurements were made in young and old AMPK KD mice and WT littermates on chow diet (CHO) or in old mice after 17 weeks of high fat diet (FA). $: Main effect of age, p<0.001. #: Main effect of diet, p<0,001. †: Main effect of genotype, p<0.005. ‡: Main effect of time, p<0.001. Values are means ± SE. n = 11–17.
Figure 2.
Basal (0 µU/ml) and insulin (500 µU/ml) stimulated glucose uptake measured in vitro in m. Soleus (SOL) and m. Extensor Digitorum Longus (EDL). Measurements were made in young and old AMPK KD mice and WT littermates on chow diet (CHO) or in old mice after 17 weeks of high fat diet (FA). *: Main effect of insulin, p<0.001. #: Main effect of diet, p<0,001. ‡: Interaction between diet and insulin action, p<0.001. Values are means ± SE. n = 11–15.
Figure 3.
Representative immuno-blots of protein phosphorylations (A) and total protein expression (B) measured by Western blot analyses in muscle lysates. Left columns are images from m. Soleus (SOL) and right columns are images from m. Extensor Digitorum Longus (EDL). Specification of phosphorylation sites and proteins evaluated are indicated on the left and estimated molecular migration points (KDa) on the gels are indicated on the right. In Figure 3A, basal and insulin-stimulated protein phosphorylations are illustrated in young and old AMPK KD mice and WT littermates on chow diet (CHO) and in old mice after 17 weeks of high fat diet (FA). Figure 3B illustrates representative images of protein expression in basal samples.
Figure 4.
Basal (0 µU/ml) and insulin (500 µU/ml) stimulated Akt Ser473 phosphorylation measured by Western blot analyses in m. Soleus (SOL) and m. Extensor Digitorum Longus (EDL). Measurements were made in young and old AMPK KD mice and WT littermates on chow diet (CHO) or in old mice after 17 weeks of high fat diet (FA). *: Main effect of insulin, p<0.001. ‡: Interaction between diet and insulin action, p<0.001. †: Main effect of genotype in either CHO fed or Old groups, p<0.05. Values are means ± SE. n = 11–15.
Figure 5.
Basal (0 µU/ml) and insulin (500 µU/ml) stimulated Akt Thr308 phosphorylation measured by Western blot analyses in m. Soleus (SOL) and m. Extensor Digitorum Longus (EDL). Measurements were made in young and old AMPK KD mice and WT littermates on chow diet (CHO) or in old mice after 17 weeks of high fat diet (FA). *: Main effect of insulin, p<0.001. ‡: Interaction between diet and insulin action, p<0.001. (‡): Trend towards interaction between diet and insulin action, p = 0.06. $: Interaction between genotype and insulin action, p<0.05. Values are means ± SE. n = 11–15.
Figure 8.
Protein content of GLUT4, HK2, TBC1D1, TBC1D4, Akt2 and TRB-3.
Protein content of GLUT4 (A), HK2 (B), TBC1D1(C), TBC1D4 (D), Akt2 (E) and TRB-3 (F) was measured by Western blot analyses in basal muscle samples from m. Soleus (SOL) and m. Extensor Digitorum Longus (EDL). Measurements were made in young and old AMPK KD mice and WT littermates on chow diet (CHO) or in old mice after 17 weeks of high fat diet (FA). #: Main effect of diet, p<0.05. $: Main effect of age, p<0.05. †: Main effect of genotype, p<0.05. Values are means ± SE. n = 11–15.
Figure 6.
TBC1D4 Thr642 phosphorylation.
Basal (0 µU/ml) and insulin (500 µU/ml) stimulated TBC1D4 Thr642 phosphorylation measured by Western blot analyses in m. Soleus (SOL) and m. Extensor Digitorum Longus (EDL). Measurements were made in young and old AMPK KD mice and WT littermates on chow diet (CHO) or in old mice after 17 weeks of high fat diet (FA). *: Main effect of insulin, p<0.001. †: Main effect of genotype, p<0.05. #: Main effect of diet, p<0.005. ‡: Interaction between diet and insulin action, p<0.001. Values are means ± SE. n = 11–15.
Figure 7.
TBC1D1 Thr590 phosphorylation.
Basal (0 µU/ml) and insulin (500 µU/ml) stimulated TBC1D1 Thr590 phosphorylation measured by Western blot analyses in m. Soleus (SOL) and m. Extensor Digitorum Longus (EDL). Measurements were made in young and old AMPK KD mice and WT littermates on chow diet (CHO) or in old mice after 17 weeks of high fat diet (FA). *: Main effect of insulin, p<0.001. #: Main effect of diet p<0.001. †: Main effect of genotype, p<0.05. Values are means ± SE. n = 11–15.