Experimental studies on the isolated humoral factor which promotes the secretory activity of the gastric chief cells and the exocrine pancreatic cells. II. Amino acids and related compounds in extracts of the gastric mucosa.

Results of a previous experiment in which the stomachs of rats were immersed in 33% alcohol and the gastric surface epithelial cells were separated so that productin of FUJIE in the surface epithelial cells might be transfused into the alcohol showed that a factor promoting production of secretory granules in the gastric chief cells (viz. productin-FUJIE) was contained in the alcohol. The presence of this factor was proved by the cytological observations of the chief cells following injection of the above mentioned alcohol into unfed rats.Chemical color testing for reaction of amino acid or protein showed the presence of a phenol group and an imidazol group in the sub-nuclear portion of the gastric surface epithelial cells where productin vacuoles are seen.Analysis by amino acid analyser showed that the alcohol after immersion of the tissue contained 18 kinds of amino acids and 5 kinds of related compounds.In this study, pure chemicals corresponding to these extracted substances were injected into unfed rats and the secretory activity of the gastric chief cells was studied morphologically in an attempt to identify a substance producing the same effects as productin.Arginine, histidine, lysine and tyrosine actively promoted the production of secretory granules in the chief cells while asparagine and serine promoted the vacuolization of the granules. The possibility of these substances as the components of productin was suggested in connection with the histochemical evidence (FUJIE et al. 1957) on the occurrence of the phenol group (tyrosine) and the imidazol group (histidine) in the surface epithelial cells of the stomach.