LTKO mice maintain euglycemic and glucose tolerant on a high-fat diet.

<p>(A) Fasting glucose levels in 4.5-month male control and LTKO mice (n=8) after the treatment with a high-fat diet for 3.5 months. (B) Non-fasting blood glucose levels in 4-month male control and LTKO mice (n=8) after the treatment with the high-fat diet for 3 months. (C, D) Glucose tolerance tests and the AUC analysis in 4.5-month male control and LTKO mice (n=8) after the treatment with the high-fat diet for 3.5 months, respectively. (E, F) Expression of genes involved in glucose metabolism was analyzed in the liver of control and LTKO mice (n=4) treated with the high-fat diet for 5 months by real-time PCR. <i>Pck1</i>, phosphoenoylpyruvate carboxykinase 1; <i>G6pc</i>, glucose-6-phosphatase, catalytic; <i>Pdk2</i>, pyruvate dehydrogenase kinase 2; <i>Gck</i>, glucokinase; <i>Pklr</i>, pyruvate kinase, liver and red blood cell type. Data represent mean ± SEM. * indicates a significance with <i>P</i><0.05 in control vs. LTKO mice.</p

Sirt6 overexpression has no significant effect on glucose toerance in LTKO mice.

<p>(A) Sirt6 overexpression was assessed by Western blot analysis in liver lysates from control and LTKO mice injected with SIRT6 or GFP adenoviruses (n=6). (B) Glucose tolerance tests in 4-month-old control and LTKO mice injected with SIRT6 or GFP adenoviruses (n=6). (C) Expression of genes involved in glucose metabolism was analyzed in the livers of SIRT6 or GFP adenovirus infected control and LTKO mice (n=6) by real-time PCR. Data represent mean ± SEM. * indicates a significance with <i>P</i><0.05 between loxp-GFP and loxp-SIRT6 groups.</p

Body composition of LTKO mice fed a high-fat diet.

<p>(A, B) Body weight and length measurements of control and LTKO mice (n=6) after a high-fat diet (HFD) treatment for 5 months, respectively. (C, D) Body fat and bone mineral density (BMD) analyses of the above HFD treated mice by DEXA, respectively. Data represent mean ± SEM.</p

Gck knockdown impairs glucose tolerance in both wild-type and LTKO mice.

<p>(A) Gck protein was analyzed in the livers of 3-month-old control and LTKO mice by Western blots. (B) Gck knockdown was assessed by Western blots in liver lysates from control and LTKO mice injected with shGck or shGFP adenoviruses. (C, D) Glucose tolerance tests and insulin tolerance tests in 6-month-old male control and LTKO mice injected with shGck or shGFP adenoviruses (n=5-6), respectively. Data represent mean ± SEM. *, <i>P</i><0.05 between LTKO-shGFP and LTKO-shGck groups; #, <i>P</i><0.05 between loxp-shGFP and loxp-shGck groups.</p

Insulin sensitivity in LTKO mice fed chow diet.

<p>(A) Insulin tolerance tests (ITT) in 3-month male control and LTKO mice (n=6) after 3-hour fasting and an intraperitoneal injection of 0.75 U human regular insulin (humulin R, Lilly) per kg body weight. (B) The data in Panel A were replotted as percentage of basal blood glucose as a function of injection time. (C) Plasma insulin levels in 4-month male control and LTKO mice (n=12) after an overnight 16-hour fasting. (D) Plasma insulin levels in 4-month male control and LTKO mice (n=6) under <i>ad libitum</i> conditions. Data represent mean ± SEM. * indicates a significance with <i>P</i><0.05 in control vs. LTKO mice.</p

Deletion of the <i>Pdk4</i> gene improves hyperglycemia in IrsLDKO mice.

<p>A, Blood glucose was measured in overnight fasted control and knockout mice. B, Blood glucose was measured in <i>ad libitum</i> fed control and knockout mice. Data are presented as means ± SEM, n = 8–23. *, <i>P</i><0.05 relative to corresponding controls.</p

Inactivation of Pdks improves insulin sensitivity in IrsLDKO mice.

<p>A, Insulin tolerance tests (ITT) were performed in age-matched control and knockout mice (n = 8–20). B, Fasting plasma insulin was analyzed in age-matched control and knockout mice (n = 5–9). C, HOMA-IR (homeostatic model assessment-insulin resistance) was analyzed using fasting glucose and insulin data. Data are presented as means ± SEM. *, <i>P</i><0.05 relative to corresponding controls.</p

Pdk2 or Pdk4 knockdown has no significant effect on insulin tolerance in IrsLDKO mice.

<p>A, Insulin tolerance tests were performed on IrsLDKO mice (n = 4–5) that were injected with shGFP, shPdk2, and shPdk4 adenoviruses. B, Area under curve was analyzed for the above ITT data. C–F, Akt phosphorylation was analyzed in the liver and skeletal muscle of mice injected with shGFP, shPdk2, and shPdk4 adenoviruses. Western blot signals were also quantified using the Quantity One software. Data are presented as means ± SEM. *, <i>P</i><0.05 relative to corresponding controls.</p

Hepatic Pdk4 knockdown moderately improves glucose tolerance in IrsLDKO mice.

<p>A, Gene knockdown efficiency was analyzed by real-time PCR in IrsLDKO livers transduced with shRNA adenoviruses against GFP (shGFP), Pdk2 (shPdk2), or Pdk4 (shPdk4). B, Glucose tolerance tests were performed in shRNA adenoviruses infected IrsLDKO mice. C, Area under curve analysis (AUC) was performed for the above glucose tolerance test data. Data are presented as means ± SEM, n = 4–5. *, <i>P</i><0.05 relative to corresponding controls.</p

Ablation of Pdks improves glucose tolerance in IrsLDKO mice.

<p>A, Glucose tolerance tests (GTT) were performed in age-matched control and knockout mice (n = 8–12). B and C, Expression of gluconeogenic genes <i>Pck1</i> and <i>G6pc</i> was analyzed in the liver of overnight fasted control and knockout mice (n = 3). Data are presented as means ± SEM. *, <i>P</i><0.05 relative to corresponding controls.</p