Preprandial single oral dose of sitagliptin does not affect circulating ghrelin and gastrin levels in normal subjects

Aims: To determine the effect of an oral dose of sitagliptin on the secretion of ghrelin and gastrin hormones. Methods: Ten healthy volunteers were recruited in this study. A baseline blood sample was drawn before oral dosing with a 100-mg tablet of sitagliptin. Two blood samples were obtained 0.5 and 1 h after dosing. Three additional postprandial blood samples were drawn at 0.5, 1, and 2 h. Radioimmunoassay was used for determining hormonal levels. A Student's t test, Pearson correlation analysis, and multivariate approach to repeated-measures analysis of variance were used for statistics. Results: After sitagliptin dosing, but before the meal, there was no significant change in circulating ghrelin, gastrin, insulin, and glucose levels. Only after meal loading was there a progressive and persistent decline in ghrelin levels until the end of the study, while a rapid and temporary rise in gastrin, insulin, and glucose levels at 0.5 h was observed. The levels of gastrin, insulin, and glucose then declined progressively. Conclusions: Preprandial oral dose of sitagliptin does not affect circulating ghrelin, gastrin, insulin, and glucose concentrations in normal subjects. Decreased ghrelin and increased gastrin and insulin levels occurred only after meal loading. These results support the theory that sitagliptin might not cause appetite-enhanced body weight gain and insulin-induced hypoglycemia.