The Effect of Cycloheximide on Cholecystokinin‐evoked Pancreatic Juice of the Anaesthetized Rat

Abstract

Summary Cholecystokinin (CCK) is a major stimulant for enzyme secretion by pancreatic acinar cells. In most animals this enzyme secretion is accompanied by a small volume of chloride‐rich “carrier” fluid in which the enzymes are dissolved. In order to determine whether this carrier fluid is secreted independently of the pancreatic digestive enzymes, and how its composition is altered by interaction with them, we have studied CCK‐evoked juice collected from anaesthetized rats before and after administration of cycloheximide. a powerful inhibitor of protein synthesis. Following treatment with cycloheximide, fluid secretion continued unchanged for 30‐40 min but protein excretion declined without appreciable delay towards aero. As protein content declined, the juice bicarbonate content rose from 30 to more than 60 mmorle I‐1 so that the juice resembled that evoked in the rat by secretin. It is concluded that secretion of CCK‐evoked fluid is independent of the secretion of digestive enzymes and that the carrier fluid is actually alkaline, like secretin‐evoked fluid, and only becomes neutral and chloride‐rich by interaction with the acidic contents of zymogen granules.

Progressive Atrophy of Pancreatic Acinar Tissue in Rats Fed a Copper-Deficient Diet Supplemented with <i>D</i>-Penicillamine or Triethylene Tetramine: Morphological and Physiological Studies

“…An alter native explanation is that the bicarbonate concentration of secretion rises in the ab sence of protein secretion. This suggestion is supported by the rise in bicarbonate concen tration of secretion evoked by caerulein which is observed after administration of cycloheximide [40],…”