PPARGC1A and obesity due to melanocortin 4 receptor deficiency: Administration of rutin in mice could modulate obesity, fatty liver and insulin resistance by increasing energy-consuming gene expressions in brown adipose tissue, including Pgc1α and Dio2, via up-regulating mitochondrial size and mitochondrial DNA (mtDNA) content, as well as those mitochondrial biogenesis-related genes, i.e. peroxisome proliferator-activated receptor γ (PARPγ), coactivator-1α (PGC-1α) and nuclear respiratory factor-1 (NRF-1) (Gao et al., 2013; Seo et al., 2015).