Gastric Acid Responses to Antral Application of Some Amino Acids, Peptides, and Isolated Fractions of a Protein Hydrolysate

Abstract

Elwin, C.-E. Gastric acid responses to antral application of some amino acids, peptides, and isolated fractions of a protein hydrolysate. Scand. J. Gastroent. 1974, 9, 239-247.

Gastric acid secretion was determined in Pavlov and Heidenhain pouch dogs in response to antral instillation or perfusion of various amino acids and peptides. Secretagogue activity was shown by amino acids with two or three carbons (glycine, β-alanine) but decreased with methylation of the amino group (sarcosine) or change of its steric location (α-alanine). Except glycylglycine, di- or tripeptides derived from glycine and alanine were less active. Irrigation of the antral pouch with two amino acids concomitantly showed an additive effect. Peptides of a protein hydrolysate (peptone) were separated by dialysis, ultrafiltration, or gelfiltration. The stimulatory potency of isolated fractions demonstrated quantitative as well as qualitative differences, which were related to molecular size of peptides and presence of free amino acids. Most pronounced effects showed the low molecular portion after ultrafiltration (mol. wt. < 1000) and some low molecular fractions after gelfiltration (mol. wt. < 200-300). The latter fractions contained free amino acids and small peptides. The stimulatory effect on acid output of peptides and amino acids thus seems to be related to their size and structure, and low molecular compounds with pronounced effects can be isolated from a protein hydrolysate.

Key-words::

• Animal experiments
• alanine
• dialysis
• gastric juice
• gastrin
• gelfiltration
• glycine
• lysine
• peptides
• stomach
• ultrafiltration