AJP - Gastrointestinal and Liver Physiology, Vol 254, Issue 3 281-G293, Copyright © 1988 by American Physiological Society
Role of blood flow in gastric acid secretion
L. Holm and M. A. Perry
Department of Physiology and Biophysics, Uppsala University, Sweden.
The relationship between gastric acid secretion and blood flow has been
investigated with a variety of different blood flow techniques including
aminopyrine clearance, hydrogen gas clearance, intravital microscopy,
laser-Doppler flowmetry, radioactive microspheres, and the elimination of
inert gases. The most commonly used technique, aminopyrine clearance,
predicts that increasing acid secretion is accompanied by a parallel
increase in blood flow. However, the efficiency of clearance of aminopyrine
is low in the nonsecreting stomach and increases as secretion rate
increases. This precludes the use of aminopyrine clearance as a reliable
measure of gastric mucosal blood flow at all but the highest steady-state
level of acid secretion and casts doubt on the findings with this
technique. Other methods for measuring blood flow indicate that there is no
simple relationship between secretion and flow, with some studies finding
that secretion and flow change in parallel and others finding that
secretion varies quite independently of flow to the mucosa. One consistent
finding is a strong correlation between stimulated acid secretion and
gastric oxygen consumption. Both acid secretion and oxygen consumption fall
if celiac blood flow is reduced below a critical value, which in the
anesthetized dog stomach is approximately 30-40 ml.min-1.100 g-1. Driving
blood flow above this value does not increase oxygen consumption and acid
secretion, i.e., they reach a plateau. The shape of this relationship with
its flow-dependent and flow-independent portions is used to explain the
apparently contradictory findings in the literature regarding gastric acid
secretion and blood flow.
