Pure Cholecystokinin: Pancreatic Protein and Bicarbonate Response

In dogs with chronic pancreatic fistulas, pure cholecystokinin (CCK), CCK-variant, 20% pure CCK, octapeptide of CCK, and caerulein all gave the same high maximal protein outputs and low maximal bicarbonate outputs. 10% pure CCK gave higher bicarbonate output than can be achieved with pure CCK. By intestinal perfusion, HCl gave greater protein output than can be achieved with secretin alone, sodium oleate gave greater bicarbonate output than can be achieved with pure CCK alone, and tryptophan gave maximal bicarbonate output less than that of pure CCK. On the hypothesis that intestinally perfused stimulants act solely by release of secretin and CCK, the effects of tryptophan can be accounted for by release of CCK alone, of HCl by release mainly of secretin plus small amounts of CCK, and of oleate by release mainly of CCK plus small amounts of secretin.