Fig. 4

In the fed state energy flux is reversed and FXR, LXR, PPARβ/δ and PPARγ are mainly involved in nutrient absorption from the gut and distribution from gut/liver to peripheral tissues, such as adipose tissue and muscle. After meals, bile acids activate intestinal FXR, promoting nutrient absorption and maintaining a barrier to the gut microbiome. Absorbed dietary lipids are transported into the circulation as chylomicrons. Hepatic FXR promotes post-prandial TAG-rich lipoprotein clearance. Excess cholesterol is removed from the body by reverse cholesterol transport under the control of the FXR-stimulated enterokine FGF19 (FGF15 in rodents) and/or activation of hepatic LXR by oxysterols. FGF15/19 attenuates post-prandial hyperglycemia by enhancing hepatic glycogenesis