CHOLECYSTOKININ-LIKE ACTIVITIES IN GUINEA PIGS AND IN DOGS OF C-TERMINAL OCTAPEPTIDE (SQ 19,844) OF CHOLECYSTOKININ

The synthetic C‐terminal octapeptide of cholecystokinin (CCK), SQ 19,844, caused CCK‐like contractile activities of excised gallbladder and ileal strips of guinea pigs, of gallbladder preparations in situ in anesthetized guinea pigs, and of gallbladder and duodenal preparations in situ in anesthetized dogs. In these preparations, SQ 19,844 was about 10 and 2.5 times more potent than CCK on a weight basis and molar basis, respectively. The duration of the effect of SQ 19,844 on the gallbladder was about one‐half that of CCK. In fasted unanesthetized dogs with gastric pouches, the secretory stimulant potency of SQ 19,844 was only about four‐fifths and one‐third that of CCK on a weight basis, and molar basis, respectively. The C‐terminal tetrapeptide, which was more potent than either SQ 19,844 or CCK as a gastric secretory stimulant, was considerably less potent in contracting the gallbladder. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company