PPARGC1B and fatty liver disease: HFD feeding strongly tended to increase the expression of peroxisome proliferator-activated receptor gamma coactivator 1-beta (Pgc1β), whereas the high dose of CNTO3649 and both doses of exendin-4 tended to reduce this HFD-induced increase in Pgc1β. Next, HFD feeding increased the expression of the lipogenic transcription factor sterol regulatory element binding protein 1c (Srebp-1c) (3.7-fold, P<0.05) (Fig. 4A) and its target gene FA synthase (Fasn) (6.7-fold, P<0.01) (Fig. 4B), which plays a role in de novo lipogenesis, contributing to HFD-induced hepatic steatosis.