Figure 6: Induced FGF21 gene expression in hepatocytes exposed to the media containing varying levels of methionine.

Mouse primary hepatocytes were cultured with an amino acid-deficient medium for 1 h followed by the indicated medium for 2 h. Using their total hepatocyte RNA, RT-qPCR was performed and relative mRNA levels were normalized to 18 S ribosomal RNA levels. (a) Hepatocytes were cultured with the medium in which the amino acid concentrations were set up comparable with those in the portal blood serum of mice fed with one of the diets (the casein, β-con, or amino acid mixture) or Williams’ E medium. All data are expressed as means ± SD (n = 3). One-way analysis of variance followed by the Bonferroni procedure was used. Different superscript letters denote statistical significance (P < 0.05). (b,c) Hepatocytes were cultured with either the β-con or AA mix medium with various concentrations of methionine for 2 h. All data are expressed as means ± SD (n = 3). Different superscript letters denote statistical significance (P < 0.05). (d) Western blot analysis of the indicated protein expression in the cells cultured with the medium containing various concentrations of methionine for 2 h. β-actin serves as a loading control. The same results were obtained in three separate experiments. (e) Schematic model of the upregulation of hepatic FGF21 gene expression caused by β-conglycinin consumption.