Effect of small intestinal glucose load on plasma ghrelin in healthy men

Abstract

Background: Postprandial ghrelin suppression arises from the interaction of meal contents with the small intestine and may relate to elevations in blood glucose and/or plasma insulin. Objective: To determine whether the suppression of ghrelin by small intestinal glucose is dependent on the glucose load and can be accounted for by changes in blood glucose and/or plasma insulin. Subjects and methods: Blood glucose, plasma insulin and plasma ghrelin levels were measured in ten healthy males (age: 32 ± 4 yr; body mass index: 25.1 ± 0.4 kg/m2) during intraduodenal glucose infusions at 1 kcal/min ("G1"), 2 kcal/min ("G2") and 4 kcal/min ("G4") and intraduodenal hypertonic saline ("control") for 120 min. Results: There was a progressive decrease in ghrelin with all treatments, control at 45 min and between 90 - 120 min (P < 0.05) and G1 (P < 0.05), G2 (P < 0.0001) and G4 (P < 0.0001) between 30 - 120 min to reach a plateau at ~ 90 min. There was no difference in plasma ghrelin between G1, G2 or G4. Control suppressed ghrelin to a lesser extent than intraduodenal glucose (P < 0.05). The suppression of ghrelin was not related to rises in blood glucose or plasma insulin. Conclusion: Suppression of ghrelin by intraduodenal glucose in healthy males is apparently independent of the glucose load and unrelated to blood glucose or insulin levels.