GGT1 and obesity due to melanocortin 4 receptor deficiency: Castaño and coworkers [19] studied the regulation of the expression of local miRNAs and circulating exosomal miRNAs in an obesity model induced by a high-fat or high-sucrose diet, these miRNAs were found to be associated with the progression of obesity and the regulation of hepatic steatosis related genes, such as PTGDS (prostaglandin D2 synthase), GGT1 (gamma-glutamyltransferase 1), HK3 (hexokinase 3), PFKP (phosphofructokinase), PKM2 (pyruvate kinase M2), SLC2A5 (solute carrier family 2 member 5), and G6PC (glucose-6-phosphatase catalase).