Abstract
1. The gastric mucosal blood flow has been measured by the amidopyrine clearance technique in anaesthetized cats. The total gastric blood flow has been (a) measured directly and (b) calculated by the Fick principle from the amidopyrine concentrations in gastric arterial and venous blood and the gastric output of amidopyrine.2. Observations on the recovery of added amidopyrine from arterial and venous blood and plasma, and on the rate of transfer of amidopyrine from corpuscles to plasma, support the underlying assumptions of the amidopyrine method of measuring mucosal blood flow.3. If acid solutions are instilled into the stomach the mucosal blood flow of the non-secreting stomach may be measured by the amidopyrine technique.4. Total gastric and mucosal blood flow increased linearly with increase in H(+) secretion, stimulated by histamine or gastrin. The increase in total flow was entirely due to the increase in mucosal flow.5. The relationship between mucosal blood flow and H(+) secretion was the same for histamine and gastrin responses, and was unaffected by maintaining the total flow at a constant level, or by reduction of the circulating blood volume. Increase in blood volume altered the relationship so that there was a greater increment in mucosal blood flow for any increase in H(+) secretion.6. It is concluded that valid observations may be made on secretion and blood flow relationships in acute anaesthetized preparations.