HNF4A and familial hypercholesterolemia: Taking into account the results of previous studies in which HNF1α and HNF4α were shown to be transcriptional activators of gene encoding PCSK9 in liver [23, 25, 49], and our hereby presented findings, we hypothesize that these hepatocyte nuclear factors through transcriptional up-regulation of gene encoding PCSK9 might contribute to the hypercholesterolemia observed in lipectomized rats.