Involvement of vitamin D in the regulation of intestinal gluconeogenesis and hepatic glycogen metabolism in K-G6pc-/- mice. (A) Plasma 1,25(OH)2 D at 6 h and 30 h of fasting in K-G6pc-/- mice. n = 5–6 per group. (B) Renal, (C) hepatic and (D) intestinal G6Pase activity at 30 h of fasting in WT-Vh, WT-VD, K-G6pc-/--Vh and K-G6pc-/--VD mice. n = 4–6 per group. (E) Intestinal gene expressions of G6pc and Pck1 at 30 h of fasting in WT-Vh, WT-VD, K-G6pc-/--Vh and K-G6pc-/--VD mice. n = 4–6 per group. (F) Hepatic glycogen and (G) G6P content at 30 h of fasting in WT-Vh, WT-VD, K-G6pc-/--Vh and K-G6pc-/--VD mice at 30 h of fasting. n = 4–6 per group. (H) Hepatic GK activity at 30 h of fasting in WT-Vh, WT-VD, K-G6pc-/--Vh and K-G6pc-/--VD mice at 30 h of fasting. n = 4–6 per group. (I) Intestinal phosphorylation state of AKT at 30 h of fasting in WT-Vh, WT-VD, K-G6pc-/--Vh and K-G6pc-/--VD mice. n = 3–4 per group. Significant differences between WT-Vh and K-G6pc-/--Vh mice are indicated. (*P < 0.05, **P < 0.01).