Hepatic SIRT1 controls systemic and hepatic cholesterol and fatty acid homeostasis. (A) Liver free fatty acids (nonesterified fatty acids), serum total cholesterol, and liver cholesterol from control shRNA-infected fed (n = 5) and 20-h fasted (n = 5) mice and SIRT1 shRNA-infected fed (n = 6) and fasted (n = 5) mice. (B) Fed, GFP (n = 6) and SIRT1 (n = 6); 19-h fasted, GFP (n = 10) and SIRT1 (n = 10). (C) GFP or SIRT1 overexpression and control or PGC-1α shRNA double-infected mice (each bar, n = 5) following a 20-h fast. Liver measurements were normalized to protein content. Similar results for all measurements have been observed in at least two independent experiments. All data are presented as the average ± SEM. Significance was determined by Student's t test. GFP/control shRNA vs. SIRT1/SIRT1 shRNA: *, P < 0.05; **, P < 0.01. Control shRNA vs. PGC-1α shRNA: #, P < 0.05.