Glucose and insulin tolerance, insulin signaling, and hepatic gene expression in mice with liver-specific deficiency of PKCλ. (a–c) Blood glucose (a) and plasma insulin (b) concentrations during a glucose-tolerance test in L-λKO and λ^lox/lox mice at 14 weeks of age, and blood glucose concentration during an insulin tolerance test at 12 weeks of age (c). Data are mean ± SEM of values from nine to 20 mice. *P < 0.05 vs. the corresponding value for λ^lox/lox mice (Student’s t test). (d) Tyrosine phosphorylation of IRS-1 and IRS-2 and serine phosphorylation of Akt in the liver of λ^lox/lox or L-λKO mice induced by a bolus injection of insulin. Liver homogenates prepared 2 minutes after administration of insulin (5 U/kg of body mass) or saline were subjected to immunoprecipitation with antibodies to IRS-1 or to IRS-2, and the resulting precipitates were subjected to immunoblot analysis with antibodies to phosphotyrosine (PY). Alternatively, liver homogenates were subjected directly to immunoblot analysis with antibodies specific for phosphorylated Akt (p-Akt). Data are representative of six mice of each genotype. (e–g) Total RNA extracted from the liver of λ^lox/lox or L-λKO mice (18 weeks of age) in the randomly fed state (n = 8) (e) or after fasting with or without refeeding (n = 4–7) (f and g) was either separately combined and subjected to Northern blot analysis (e and f) or subjected individually to RT-PCR analysis (g) for the indicated mRNA’s. Ethidium bromide staining of 28S rRNA is also shown for Northern analysis. *P < 0.01 (ANOVA). (h) The nuclear fraction of liver homogenates prepared from λ^lox/lox or L-λKO mice after fasting with or without refeeding was subjected to immunoblot analysis with antibodies to SREBP-1c. Data shown are from two mice and are representative of four to six animals. (i and j) Mice (λ^lox/lox or L-λKO) 16–18 weeks of age (n = 10–16) were injected with AxCAMyr-p110 or AxCALacZ and were subsequently deprived of food for 16 hours. The abundance of Myr-p110 in liver homogenates was then examined by immunoblot analysis with antibodies to Myc (i, upper panel), blood glucose concentration was determined (i, lower panel), and the amounts of Srebp1 and Fas mRNA’s among separately combined total RNA extracted from the liver were evaluated by Northern analysis (j). *P < 0.05, **P < 0.01 (ANOVA). (k) Total RNA extracted from the liver of λ^lox/lox or L-λKO mice treated with either T0901317 or vehicle was separately combined and subjected to Northern blot analysis for Srebp1 and Fas mRNA’s. Data are shown for two mice and are representative of four animals.