AJP - Gastrointestinal and Liver Physiology, Vol 242, Issue 2 85-G88, Copyright © 1982 by American Physiological Society
Stimulation of gastric acid secreted by glycine and related oligopeptides in humans
A. Wald and S. A. Adibi
To investigate the effect of oligopeptides on gastric secretion in humans,
we investigated acid secretion in healthy volunteers after the intragastric
infusion of physiological saline, glycine (100 mM), diglycine (50 mM),
triglycine (33 mM), and tetraglycine (25 mM). All test solutions were
equivalent in glycine content, osmolality (300 mosmol), and pH (5.5).
Although the rate of acid secretion was greater during glycine than saline
infusion [5.6 +/- 0.8 vs. 3.3 +/- 1.1 mmol/h (means +/- SE); P less than
0.05], the rate of acid secretion during glycine infusion was not
significantly different from that induced by its related peptides. There
were increases in plasma glycine concentration during infusion of glycine
and its related peptides but no detectable changes in serum gastrin levels.
The increases in plasma glycine must have been due to absorption from the
small intestine because there was no gastric absorption of glycine in free
or dipeptide form nor diglycine hydrolysis in the stomach. Therefore, our
results permit implicating only the increased plasma glycine concentrations
as the stimulus for acid secretion by glycine and its homologous peptides.
