The measurement of dog gastric mucosal blood flow by radioactive aniline clearance compared with amidopyrine clearance.

1. Methods for the estimation of radioactive aniline in body fluids are described. The recovery of aniline added to blood, plasma and gastric juice was over 90% of the recovery from saline.2. In the doses used aniline caused methaemoglobinaemia of 5-11% of total haemoglobin. No other effect was detected. Gastric secretion was also unaffected.3. Aniline clearance increased in parallel with acid secretion from Heidenhain pouches in conscious dogs and in anaesthetized dogs. In conscious dogs the ratio of aniline clearance to acid secretion was significantly higher for histamine stimulation than for pentagastrin stimulation.4. Aniline and amidopyrine clearances were compared simultaneously in the same dogs. Aniline clearance was about 80% of amidopyrine clearance.5. The proportion of aniline bound to plasma proteins was measured by two methods and found to be 25%. When aniline clearance was corrected for plasma binding, aniline and amidopyrine clearances were equal.