GCG and obesity due to melanocortin 4 receptor deficiency: As one of the most important gut hormones, glucagon-like peptide 1 (GLP-1) stimulates glucose-dependent insulin secretion and consequently improves metabolic syndromes, such as obesity and T2DM.34 In the current study, the serum GLP-1 level was significantly reduced by HFD (P < .05 compared with the NCD group; P < .01 compared with the NCD+PHZ group); however, such effect was significantly inhibited by PHZ supplementation (P < .05; Figure 1k).