Measurement of gastric acid secretion in the rat by test meal: effects of distension, pentagastrin and propantheline.

Abstract

Accuracy of a modified test meal technic was assessed by measurement of gastric acid secretion and emptying in male Wistar rats under various conditions. Secretion was higher when a 10% dextrose solution was given during fasting, than when only water was allowed. A 48-hour fast with 10% dextrose solution ad libitum was optimal. The coefficients of variation, for acid output and gastric emptying obtained by duplicate tests under resting conditions, ranged from 18 to 30%. Oral propantheline bromide inhibited acid secretion. The degree of inhibition was similar for measurements by test meal and after pyloric ligation. Pentagastrin produced a highly significant increase in acid secretion. The dose required to evoke a maximal response is considerably higher in the rat than in man. Serial measurements, with test meal volumes of 5, 7.5 and 10 ml, and with graded doses of pentagastrin, revealed no relationship between gastric acid secretion and test meal volume. Hence, distension may be physiologically unimportant in the control of gastric secretion in this species; assessment of secretion by test meal does not require that test meal volume be regulated accurately according to the size of the rat. Incomplete emptying of the stomach, and failure to recover all marker (phenol red) at the end of the test period, result in overestimation of gastric emptying and, to a lesser extent, of acid secretion. The significance of these errors can be minimized by the use of a large volume test meal.