EFFECTS OF HYPERGLYCEMIA ON INTERDIGESTIVE GASTROINTESTINAL MOTILITY IN HUMANS

Background: Gastrointestinal motility disorders are common in patients with diabetes mellitus. Recent studies indicate that hyperglycemia ca n affect gastric emptying and gastric motility in healthy subjects and diabetics. Methods: The effect of acute hyperglycemia on gastrointest inal motility was studied with a manometric technique in healthy subje cts. Seven individuals, four men and three women, 23-34 years old. wer e studied on 2 different days. On 1 of the days a 5-h registration was performed after an overnight fast. On another day and after an initia l basal period, acute steady-state hyperglycemia was induced by intrav enous glucose infusion for 90 min. Motility variables were evaluated i n four segments: in the gastric antrum, the proximal duodenum, the dis tal duodenum, and the proximal jejunum. Results: Fasting migrating mot or complex rhythm including migration of phase III prevailed during hy perglycemia. Compared with euglycemia, the motility index in phase II was lower during hyperglycemia in all segments studied. In the antrum the difference was 62% (p < 0.01); in the proximal duodenum, 37% (p<0. 01); in the distal duodenum, 44% (p<0.05); and in the jejunum, 58% (p < 0.01). During hyperglycemia the prevalence of propagated contraction s in phase II was significantly lower than during euglycemia both in t he antrum and the proximal duodenum. In the last part of phase III in proximal duodenum most individual contractions were propagated in orad direction compared with early phase III, and this difference persiste d during hyperglycemia. The number of long clusters was significantly increased during hyperglycemia as compared with euglycemia: 2.0 +/- 0. 6 per hour versus 0.4 +/- 0.14 (p < 0.01). In late phase II plasma lev els of motilin and pancreatic polypeptide were significantly decreased during hyperglycemia. Conclusion: Hyperglycemia not only reduces the motility in the stomach but also inhibits motility in both the duodenu m and the jejunum. The results show that acute hyperglycemia has an im portant impact on small-intestinal motility.