EFFECT OF EUGLYCEMIC HYPERINSULINEMIA ON GASTRIC-EMPTYING AND GASTROINTESTINAL HORMONE RESPONSES IN NORMAL SUBJECTS

Several studies have shown that hyperglycaemia slows gastric emptying in normal subjects and patients with diabetes mellitus but whether hyp erinsulinaemia per se has an effect remains debatable. In the present study we have assessed the effect of hyperinsulinaemia on gastric empt ying of a solid and liquid meal in normal subjects. Ten men were studi ed three times in random order. After an overnight fast, subjects were infused with 0.9% NaCl on two occasions and on the third with insulin , at 40 mU.m(-2).min(-1) with 20 % glucose simultaneously to maintain euglycaemia. Steady-state glucose infusion rate was ensured before the subjects ate a standard meal of a pancake labelled with Tc-99m and mi lk-shake labelled with In-111-DTPA. Gamma-scintigraphic images were th en obtained every 20 min for the next 3 h. There were no significant d ifferences between the mean half-emptying times (T-50) of the solid an d liquid during the two saline infusions (129.6 +/- 25.5 vs 128.4 +/- 23.8 min for the solid and 25.4 +/- 7.0 vs 34.7 +/- 18.0 min for the l iquid, mean +/- SD). Hyperinsulinaemia delayed both solid (mean T-50 1 49.6 +/- 30.7, p = 0.031) and liquid emptying (mean T-50 39.8 +/- 13.9 , p = 0.042). There were no significant differences in the cholecystok inin and glucagon-like peptide 1 responses to the meal during either s aline or insulin infusions. There was a tendency towards a greater ins ulin response to the meal during the hyperinsulinaemic study. Thus, hy perinsulinaemia delayed emptying of both the solid and liquid componen ts of the meal.