In conclusion, we have shown that blood flow response in portal vein to a mixed-meal is enhanced and GLP-1 secretion is stimulated early after bariatric surgery in morbidly obese subjects with T2D, suggesting that the altered gastrointestinal anatomy in the post-bariatric state improves digestion and nutrient absorption also by influencing splanchnic blood flow. The gene discussed is GCG; the disease is type 2 diabetes mellitus.