AJP - Gastrointestinal and Liver Physiology, Vol 243, Issue 5 341-G347, Copyright © 1982 by American Physiological Society
Importance of dietary amines in meal-induced gastrin release
L. M. Lichtenberger, L. A. Graziani and W. P. Dubinsky
The dietary chemical constituents responsible for initiating the gastrin
secretory response to a meal have yet to be identified. The evidence
supporting the importance of dietary amino acids in the initiation of the
postprandial release of gastrin is both conflicting and unconvincing. In
this study we investigated the role of the amino acid breakdown products
ammonia and the amines in the regulation of gastrin release both in vivo
and in vitro. Lyophilization of standard rat food under alkaline conditions
results in the volatilization of both ammonia and the amines, which can be
subsequently condensed in a cold trap. The normal postprandial release of
gastrin is significantly reduced by approximately 50% when rats are fed
this freeze-dried diet. Addition of the amine-containing condensate back to
the freeze-dried diet completely restores this response to normal. Analysis
of the completely restores this response to normal. Analysis of the
condensate by thin-layer chromatography revealed that it contained ammonia,
methylamine, ethylamine, dimethylamine, and a fourth unidentified aliphatic
amine. All of the above compounds significantly stimulated the release of
gastrin from isolated G cells. Similarly, addition of ammonia and a
synthetic amine mixture to the freeze-dried diet completely restored the
postprandial release of gastrin to normal levels. In conclusion, our
results suggest that dietary amines and ammonia may play a key role in
initiating the gastrin secretory response to a meal.
