Glucose and gastrointestinal hormones in response to surgery. Blood glucose values (A), change in GLP-1 levels from baseline at 10 min (B) and fasting ghrelin levels before a mixed-meal tolerance test (MMT) in the HFD rats (6C). Blood glucose values of DR, PR, and VSG were significantly lower than those of sham at 60 min. DR and PR blood glucose values were significantly lower at 30 min. Fasting ghrelin levels were significantly lower in VSG, as compared with DR, PR, and sham. GLP-1 secretion matched the gastric emptying rate (GER) for the four groups. Different letters indicate statistical significance, P < 0.05. *Significantly different vs. sham, P < 0.05.