The histamine test meal in the rat.

A histamine test meal is described for the estimation of the secretion of gastric acid and pepsin in the unanaesthetized intact rat. The stomach of the rat secreted pepsin and a small amount of acid in response to the test meal of hypertonic sucrose. Stimulation with histamine produced a pronounced rise in acid secretion but the output of pepsin remained unchanged. The increase in acid secretion was correlated in the individual rat with a rise in the volume of gastric secretion. Histamine phosphate in a dose of 50 mg./kg. body weight produced maximal stimulation of gastric acid secretion and was free from toxic effects. Choline chloride, in a dose of 126.5 mg./kg. body weight, had no effect on the volume of gastric secretion and it was ineffective as a stimulant of either acid or pepsin secretion.