The mRNA levels of JMJD3 and KLB were decreased, whereas those of Fgfr1 and Fgfr4 were increased, after feeding a HFD (Fig. 8b), suggesting that decreased expression of KLB may contribute to FGF21 resistance in obesity. This evidence concerns the gene FGFR1 and obesity due to melanocortin 4 receptor deficiency.