ABSTRACT
The gastric emptying of maltose, sucrose, lactose and lactulose was compared in young adult ratswith ontogenic lactase deficiency. Eight animalswere employed for each sugar meal at each time od study (total number of animals = 192). Each animal received a test meal consisting of a solution of the sugar (100 mg/ml) and phenol red as marker and gastric retention was measured at 5,10,20,30,45 and 60 min after orogastric infusion of the test meal. Gastric retention was determined by measuring the concentration of the marker in the residual test meal recovered from the stomach after killing the animal. There was no difference between the gastric emptying of lactose and lactulose. The gastric emptying of maltose was significantly slower during the initial 30 min and the emptying of sucrose was identical to that of maltose only at 5 min and could not be distinguished from that oflactose and lactulose at later times. These data support the observation, made in human subjects, that under conditions of ontogenic lactase deficiency, the modulation of gastric emptying of lactose is ineffective. It is possible that the rapid emptying of sucrose is due to the saturation of sucrase because of substrate overload which impairs the intestinal inhibitory control of gastric emptying