Figure 2.
Activation of Sirt1 by resveratrol decreases fat accumulation in differentiated adipocytes. a, Resveratrol addition to 3T3-L1 cells first fully differentiated into adipocytes. At day 12, resveratrol dissolved in DMSO was added in increasing concentrations (1, 10, 50 and 100 µM; as indicated) and Oil red O staining was performed 3 days later and compared with cells incubated with DMSO alone (resveratrol 0 µM). b, c, Effect of resveratrol on 3T3-L1 cells infected with the indicated viruses. Cells were differentiated into adipocytes as in Fig. 1d. At day 12, resveratrol (50 µM) was added and 3 days later, intracellular triglyceride content was evaluated by Oil red O staining (b) and in cell lysates (c). FFA released in the medium during the 3-day incubation period was also measured (c). Open bars, control; filled bars, resveratrol. d, e, Effect of resveratrol on primary adipocytes isolated from rat retroperitoneal WAT. Cells were incubated with or without adrenalin (10−7 and 10−5 M for d and e, respectively) in the presence of Sirt1 activator (resveratrol, d) or inhibitor (nicotinamide, e). FFA levels released in the medium were measured after 4 h (d) or at indicated time points (e). Data shown are means ± s.e.m. and were obtained from two independent experiments done in triplicate. Asterisk indicates a statistical difference from respective control (P < 0.05).