Retardation of gastric emptying of solid food by secretin.

The effect of secretin at nearly physiologic plasma concentrations on the gastric emptying rate of solid food was studied in 12 healthy men. A 99mTc colloid-labeled pancake was used as the test meal. The gastric emptying rate was measured during 1 h using a dual-headed gamma-camera, and was expressed as the half-time of the emptying curve. To prevent endogenous secretin release, 400 mg of cimetidine was given before the meal. Subjects were studied under three conditions: (1) during infusion of saline; (2) during continuous infusion of secretin, 6.6 pmol/kg.h; and (3) during three intermittent 10-min periods of secretin infusion, 7.6 pmol/kg.h during each period. Both continuous and intermittent infusion of secretin increased half-emptying time, by 133% and 55%, respectively. The plasma secretin concentration in condition 1 was 0.8 pM; plateau concentration in condition 2 was 9.8 pM; and integrated mean concentration in condition 3 was 4.8 pM. It is concluded that secretin at approximately physiologic plasma concentrations retards gastric emptying of solid food in humans.