CHOLECYSTOKININ DOES NOT DELAY GASTRIC-EMPTYING OF REGULAR MEALS IN HEALTHY HUMANS

Exogenous CCK can delay gastric emptying of meals in the experimental animal and in humans. Studies using exogenous CCK, however, do not prove that the effects of exogenous peptide are of physiological importance. For this reason, the present study employed the specific CCK-antagonist loxiglumide (Rotta) to investigate the question as to whether CCK plays a physiological role in the regulation of gastric emptying. (1) Sonographic studies: Fourteen healthy subjects received a mixed solid-liquid 1,000 kcal meal made up of regular German food. Gastric emptying was calculated from antral volumes measured at 10-minute intervals. All subjects were studied twice on separate days, either with or without i.v. infusion of 1.0, 5.0 or 10.0 mg/kg h loxiglumide, each different dose being given to 4 or 5 subjects. (2) Scintigraphic studies: Eight subjects received an 800 kcal mixed solid-liquid meal consisting of regular food. Solid and liquid components were labeled with 99m-Tc and 113m-In, respectively. Gastric emptying was monitored using a computerized gamma-camera. All subjects were studied twice on separate days either with or without i. v. infusion of 5 mg/ kg h loxiglumide. Both meals significantly increased plasma activity of CCK by 4-8pM/ml (bioassay). However, loxiglumide did not significantly alter gastric emptying at any postprandial time when compared with the NaCl control. The failure of the CCK-antagonist to affect gastric emptying was seen with both type of meals and both the sonographic and scintigraphic techniques. In the scintigraphic studies, gastric emptying of both liquid and solid components were virtually identical in experiments with or without loxiglumide. In contrast to the lack of effect on gastric emptying, loxiglumide completely abolished meal-induced gallbladder emptying in all studies and subjects as assessed by sonographic monitoring. In conclusion, CCK does not play a physiological role in the regulation pf gastric emptying of solid and liquid components of regular meals in healthy humans.