THE INHIBITION OF GASTRIC SECRETION BY THE INTRAVENOUS INJECTION OF CALCIUM SALTS

Abstract

In 17 dogs under acute exptl. conditions a total of 29 injs. of Ca salts (4.3-13 mg. Ca per kg. body wt.) given when a constant rate of secretion was established either by histamine (21 times) or by vagal stimulation (8 times), caused a reduction in the rate of secretion in all cases. This reduction in the 15-min. vol. averaged 75% of the control vol. for the whole series (range 22.5%-99.2%). The inhibition was maximum 45 min. after the inj. (range 30-67 min.) and had ended in 75 min. (range 52-105). Following the period of inhibition in some cases an increase over the control vol. of secretion occurred. The inhibitory agent. was probably the Ca radicle since inj. of equivalent amts. of lactate (the form in which the Ca was as a rule given) as the Na salt did not cause inhibition, while equivalent amts. of Ca as the chloride had the same effect as Ca lactate. Osmotic pressure changes appeared to be ruled out as the cause of the inhibition since isotonic solns. were used, changes in urinary excretion were slight and the osmotic pressure of samples of blood (freezing-point method) at the critical stages of a typical expt. showed no significant change from normal. Circulatory changes (general blood pressure and blood flow through the stomach) could not be correlated with the changes in secretion rate caused by Ca.