Hepatic STAT3 phosphorylation in response to IL-6 in vivo. (A) Hepatic levels of phosphorylated STAT3 (P-STAT3), total STAT3, and GAPDH were determined using immunoblot techniques in Alk2^fl/fl and Alk2^fl/fl; Alb-Cre mice 72 hours after injection with Ad.GFP or Ad.IL-6. (B) Hepatic levels of P-STAT3, total STAT3, and GAPDH were determined using immunoblot techniques in Alk3^fl/fl and Alk3^fl/fl; Alb-Cre mice injected with Ad.GFP or Ad.IL-6 for 72 hours. (C) Hepatic HO-1 mRNA levels 72 hours after injection of Ad.GFP or Ad.IL-6 were determined by quantitative RT-PCR (1-way ANOVA, P = .0038; *P = .02: Alk2^fl/fl injected with Ad.GFP [n = 3] vs Alk2^fl/fl injected with Ad.IL-6 [n = 5]; ^#P = .005: Alk2^fl/fl; Alb-Cre mice injected with Ad.GFP [n = 4] vs Alk2^fl/fl; Alb-Cre mice injected with Ad.IL-6 [n = 7]). There was no difference between hepatic HO-1 mRNA levels in Alk2^fl/fl and Alk2^fl/fl; Alb-Cre mice after injection with Ad.IL-6. (D) Hepatic HO-1 mRNA levels in Alk3^fl/fl and Alk3^fl/fl; Alb-Cre mice (1-way ANOVA, P = .007; *P = .0074: Alk3^fl/fl injected with Ad.GFP vs Alk3^fl/fl injected with Ad.IL-6 [n = 5]; ^#P = .02: Alk3^fl/fl; Alb-Cre mice injected with Ad.GFP [n = 6] vs Alk3^fl/fl; Alb-Cre mice injected with Ad.IL-6 [n = 5]).