Effect of plasma H+‐ion concentration on pancreatic HCO‐3 secretion

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Abstract
The relationship between the rate of pancreatic HCO‐3 secretion and plasma H+‐ion concentration was investigated in 15 pentothal anesthetized, secretin infused pigs (1.8 C.U./kg b.w. h‐1 intravenously) during acute metabolic and respiratory acid‐base disturbances. Pancreatic HCO‐3 secretion increased to 196 ± 10% of control during alkalosis and fell to 41 ± 4% of control during acidosis. Partial metabolic compensation of respiratory acidosis restored HCO‐3 secretion to 87 ± 6% of control. A proportional relationship was found between HCO‐3 secretion and plasma pH. Different, proportional relationships were found between HCO‐3 secretion and plasma HCO‐3 concentration during metabolic and respiratory acid‐base changes. HCO‐3 secretion was independent of H+‐ion concentration in pancreatic juice. Plasma H+‐ion concentration, therefore, seems to determine the rate of pancreatic HCO‐3 secretion. This finding supports the hypothesis that a proton pump is responsible for pancreatic HCO‐3 secretion.