HYPERINSULINEMIA IMPAIRS GASTROINTESTINAL MOTILITY AND SLOWS CARBOHYDRATE-ABSORPTION

Experimental euglycaemic hyperinsulinaemia (insulin levels 46 +/- 4 mU /l) impaired the postabsorptive gastrointestinal motility in healthy i ndividuals; the effect being particularly pronounced in the upper gast rointestinal tract (stomach and proximal duodenum). The postprandial g astric emptying, measured with a standardized Tc-99m labelled meal, wa s also significantly delayed (t(50) increased by 38% or 32 min). This was combined with a slower carbohydrate absorption (delay in peak bloo d glucose level about 40 min). Furthermore, during experimental hyperi nsulinaemia higher blood glucose levels were seen at 120 min than at 6 0 min after food ingestion. This was not seen in any subject in the co ntrol study where only 0.9% NaCl was infused. Blood levels of the moti lity-stimulating hormone, motilin, were significantly lower during exp erimental hyperinsulinaemia. Thus, experimental hyperinsulinaemia impa irs the gastrointestinal motility in both the postabsorptive and postp randial states. This effect is combined with a delayed carbohydrate ab sorption. Hyperinsulinaemia per se may thus lead to alterations in car bohydrate absorption and can also contribute to the gastrointestinal d isturbances in diabetes.