POMC and Behcet disease: Our results showed that the serum levels of GLP-1, its upstream receptor TGR5, and its downstream molecule insulin were not significantly changed in the BD group, which may be because biliary diversion to the ileum did not change the rate of nutrient entry into the intestine (42), which suggests that there are other signaling molecules and pathways responsible for the upregulation of the POMC gene, such as the bile acids that have significantly changed after bariatric surgery.