Intravenous Histamine and Gastric Pepsin in the Unanesthetized Dog

Abstract

After one hour of collection of gastric content from gastric and duodenal fistulae in unanesthetized dogs, a continuous intravenous infusion of 1.8 [mu]g of histamine base/kg body weight was given for 3 hours. Gastric content volume rose to 48 ml [plus or minus] 11/15 min. in the 2d hour with a concentration of 146 [plus or minus] 23 mEq/l total acid and an output of 6.95 [plus or minus] 1.64 mEq/15 min. Pepsin concentration by the hemoglobin substrate method fell from 21 [plus or minus] 22 mg crystalline pepsin x 10-2/ ml in the 1st half hour of infusion to 3+4 in the 3d hour, while output fell from 227 [plus or minus] 175 mg crystalline pepsin x 10-2/15 min. to 35 [plus or minus] 9 in the 3d hour. These results indicate an early washout and a small continued secretion of pepsin in response to histamine.