SREBF1 and steatosis: To evaluate whether the lower steatosis observed in iPgc1α-/- mice was caused by changes in the synthesis of new fatty acids, we assessed the expression of Sterol regulatory element-binding protein 1 (Srebp1c), Fatty acid synthase (Fasn), and Stearoyl-CoA desaturase 1 (Scd1), observing a significantly decreased expression of the de novo lipogenesis genes in iPgc1α-/- mice compared with controls (Fig. 3I).