Stress-related diseases, neural protection, neurological inflammation, and neurogenesis are all affected by the PYY, which may activate Y4 receptors and then engage in anxiety and depression regulation.228 GLP-1 is well-recognized as a hormone that stimulates glucose-dependent insulin production, and also responds to brain diseases like PD and depression via the GLP-1 receptor. Here, GCG is linked to major depressive disorder.