APLNR and steatosis: Studies have found that Apelin–APJ signaling in hepatocytes protects receptor-mediated steatosis in human and mouse hepatocytes via AMPK and PPARα [54], consistent with findings from this study that revealed that the enrichment of circadian rhythm genes in pathways such as the PPAR, AMPK, and APJ signaling pathways is lost in the sheep liver after SD.