APOE and familial hypercholesterolemia: Previous findings of MC1R mRNA expression in the rat and human liver (Gatti et al., 2006; López et al., 2007; Malik et al., 2012) and that global MC1-R deficiency aggravated hypercholesterolemia in Apoe-/- mice (Rinne et al., 2018) led us to hypothesize that MC1-R regulates cholesterol metabolism in hepatocytes.