Cholecystokinin intestinal extracts

As early as in 1856 the observation was made by Claude Bernard that introduction of hydrochloric acid into the duodenum causes the flow of bile. In the nineteen-twenties, Ivy and his coworkers proved the presence of cholecystokinin in intestinal extracts, but the gall bladder contracting hormone was isolated, from hog intestines, only several decades later, by the efforts of J.E. Jorpes and V. Mutt (Plate 23) [2] who concluded their study with the elucidation of the structure [115]. The 33-residue sequence of cholecystokinin (CCK, porcine). 

Chicken cholecystokinins 8 and 9 were extracted from intestine and purified Ity size exclusion and Cig reversed-phase HPLC. The final analysis step involved the use of a Cj colunm (A = 214nm) and a 45-min 95/5/0.1 -> 55/450.1 water/ acetonitrile/TFA gradient [1314]. Baseline resolution and excellent peak shapes were obtained. 

Experiments performed in the 1920s and already described showed that acid and food, in particular fat, in the duodenum inhibit gastric secretion. Lim and his collaborator Kosaka made an extract of the duodenal mucosa that, upon intravenous injection into a dog, inhibited food-stimulated acid secretion, and they called the active component of their extract enterogastrone. Kosaka and Lim demonstrated that their extract did not stimulate pancreatic or biliary secretion and therefore did not contain secretin or cholecystokinin. In the 1960s, when it was possible to isolate purer and more potent compounds from the duodenal mucosa, R. A, Gregory extended the definition of enterogastrone to include inhibitors released from the intestine by acid and hypertonic solutions as well as by fat. " ... 

Since our crude material extracted from the intestinal mucosa for the preparation of secretin contained cholecystokinin and pancreozymin as well, the methanol-insoluble material left after extracting the secretin was fractionated with ethanol and chromatographed on carboxymethyl cellulose. The material obtained could be used in man (Werner and Mutt 1954, Werner 1956), 3-4 mg of substance being injected intravenously for the cholecysto-graphic test. The cholecystokinin activity was 22 Ivy dog imits/ mg and the pancreozymin activity 100-120 units/mg as defined by Grick, Harper and Raper (1949) (Jorpes and Mutt 1959, 1961 a). 

Cholecystokinin, a hormone evoking contraction of the gall bladder, resembles secretin in its distribution, and is present in extracts of the intestinal mucosa. Separation of the two hormones has been claimed by Ivy and Oldberg (1928). 

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