The glucose homeostasis will be evaluated by a modified oral glucose tolerance test (OGTT). In addition, we will assess GI symptoms and hemodynamics before and after oral glucose (at minute 0, 30, 60, 90, and 120). The plasma levels of GI peptides (GLP-1, GLP-2, PYY, glucagon, C-peptide, insulin) will be measured in different time points after oral glucose. Gastric emptying will be evaluated by acetaminophen absorption test (AAT). The LPS (lipopolysaccharide), LBP (lipopolysaccharid-binding protein), sCD14, and I-FABP (faty acid-binding protein) as GUT cells damage markers will be measured at baseline. The following technics will be used in this study: