Correlation of in vitro Activity of Normal Human Gastric Juice on Casein at pH 7.4 with Gastric Intrinsic Factor

Abstract

The administration of mixtures of normal human gastric juice (intrinsic factor) and beef muscle (extrinsic factor) at pH 5 or 7 to patients with pernicious anemia results in increased blood production and clinical improvement,1,2In 1930, in association with Dr. C. W. Heath, unsuccessful attempts were made to show that gastric juice at pH 7.4 caused the production of amino acid from beef muscle. Griffiths3 showed that gastric juice incubated with beef muscle globulin at pH 6 produced certain chemical changes. Emerson and Helmer4 could not confirm his results. However, the present observations show that when casein was substituted for beef muscle, gastric juice at pH 7.4 did produce progressive changes in the casein.Normal human gastric juice was obtained free from bile after injection of histamine, filtered through gauze and placed in the ice box. A one percent solution of A. H. Thomas & Company washed casein was prepared at pH 7.4, avoiding excess of acid or alkali. To 50 ml. of this solution were added 5...