Figure 12. Heterotopic expression of osteocalcin reduces lipid deposition in the liver and rescues insulin signaling.

(A) Oil Red O staining on frozen liver sections of EV- and wtOCN and μOCN vector–receiving mice treated with 1.5 mg corticosterone per week or placebo. Original magnification, ×200. CS, corticosterone. (B) Quantification of Oil Red O in frozen liver sections. Bars represent the percentage of lipid-stained area over total measured area. (C) Western blot of total InsR of cell lysate collected from isolated primary hepatocytes of EV- and wtOCN and μOCN vector–receiving mice. Cells were treated for 24 hours with either corticosterone (100 mM) or placebo. Density ratios were calculated using Quantity One software. (D) Western blot of phosphorylated InsR (p-InsR) of cell lysate collected from isolated primary hepatocytes of EV- and wtOCN and μOCN vector–receiving mice. Cells were treated for 24 hours with either corticosterone (100 mM) or placebo and stimulated with insulin (50 nM) or placebo 5 minutes before lysis. ^†P < 0.001 compared with respective vector-receiving placebo-treated controls, ^##P < 0.001 compared with other corticosterone-treated groups receiving μOCN vectors (2-way ANOVA followed by post-hoc analysis; error bars represent SEM).