GCG and obesity due to melanocortin 4 receptor deficiency: Moreover, FB3-14 treatment also reprogrammed the intestinal microbial composition; promoted the abundance of Akkermansia muciniphila, unclassified_Muribaculaceae, Lachnospiraceae_NK4A136_group, and Bifidobacterim, which were inversely associated with obesity-related parameters; and might enhance the secretion of PYY and GLP-1 by upregulating the butyric acid level mediating GPR41.