Cholecystokinin is a physiological hormonal mediator of fat-induced inhibition of gastric emptying in man.

The effect of cholecystokinin-33 on gastric emptying was studied in eight healthy men. The test meal was a firm custard pudding, labelled with 99mTc-Chelex-100 particles. Gastric emptying rate was measured, using a dual-headed gamma camera, and was expressed as the half time of the emptying curve. Plasma cholecystokinin concentrations were determined by radioimmunoassay. Subjects were studied three times: (i) during infusion of saline; during cholecystokinin infusion, (ii) 0.375 IDU kg-1 h-1 and (iii) 0.75 IDU kg-1 h-1. Furthermore, plasma cholecystokinin was determined after a regular meal. During saline, plasma cholecystokinin increased minimally. After the regular meal it increased from 1.6 to 6.5 pmol l-1 at 30 min, decreasing to 5.3 pmol l-1 at 60 min. During the lower and higher doses of cholecystokinin it increased from 1.0 and 1.4 to 4.5 and 7.3 pmol l-1, respectively. The lower and higher doses significantly (P less than 0.05) increased half emptying time, from 45 +/- 8 to 86 +/- 17 and 198 +/- 50 min, respectively. Cholecystokinin is most likely a physiological hormonal mediator of fat-induced inhibition of gastric emptying.