Using a series of complementary approaches with specific modulation of the gut microbiota (antibiotics, prebiotics) or pharmacological inhibition or activation of the GLP-2 receptor, it was shown that the gut microbiota and the enterohormone GLP-2 both participate in gut barrier function and further associate with systemic and hepatic inflammation associated with obesity and T2D [128]. This evidence concerns the gene GCG and obesity due to melanocortin 4 receptor deficiency.