Pancreatitis Pancreozymin

Cholecystokinin (= Pancreozymin)] (4kDa protein) Animals brain GI tract CCK-R agonist ianorexigenic, nociception, T pancreatic exocrine secretion, J- gastric emptying]... 

Somatostatin has been found to inhibit the secretion of various other hormones such as thyrotropin, gastrin inhibitory peptide (GIP), vasoactive intestinal peptide (VIP), pancreozymin, secretin, motilin, gastrin, renin, ACTH in patients with ACTH-secreting pituitary adenoma and ACTH-secretion vitro and to effect exocrine pancreatic function and various GI functions. "21 The physiological significance of these findings is not clear at the present time. 

In the small intestine, pancreozymin causes the gallbladder to contract, and bile, a micellar solution of bile acids, lecithin, and cholesterol, is secreted into the duodenum. Pancreozymin also causes discharge and continued synthesis of pancreatic lipase which adsorbs to the oil-water interface, liberating 2-monoglycerides and fatty acids (76). Whether bile acids adsorb to the interface and if so how they spatially orient with respect to lipolytic products and lipase is unknown. At concentrations below the CMC, bile acids will adsorb to monolayers of lipolytic products (77), but no information is available on the interaction of bile acid solutions above their CMC with monolayers of lipolytic products. Somehow, the lipolytic products are transferred to the bulk phase, where they form mixed micelles with bile acid molecules (Fig. 14). 

Cholecystokinin, pancreozymin a tissue hormone consisting of 33 amino acids (porcine), Jlf, 3,838. It is formed in the mucosa of the upper intestine in response to the presence of chyme (add mixture of partially digested food) or to a nervous stimulus, and promotes contraction of the gall bladder and secretion of pancreatic juice. [F.Ctecelebi L.J. Miller J. Biol. Chem. 270 (1995) 3435-3441]... 

Two hormones are involved in pancreatic secretion secretin and pancreozymin. In the early 1900 s, researchers observed that dilute hydrochloric acid placed in the duodenum stimulated pancreatic secretion. Bayliss and Starling prepared an acid extract of the intestinal mucosa, injected it, and observed pancreatic stimulation. This was the first instance of a nonnervous transmission of a stimulus. Bayliss and Starling boldly coined the word hormone to refer to this type of new agent and called the first hormone secretin. ... 

In 1943, Harper and Paper (bottom right) demonstrated that extracts of the mucosa of the upper intestine contained a substance that, on intravenous administration, stimulated the pancreas to secrete enzymes (amylase) as opposed to secretin, which stimulated water and bicarbonate secretion. In addition, no effect on volume output was noted. The British researchers proposed the name pancreozymin to describe the former (background). Thereafter, in 1966, the peptide chemists Jorpes and Mutt demonstrated that CCK and pancreozymin shared the same chemical structure and that the two biologic effects-of gall bladder contraction and pancreatic enzyme secretion—were induced by this agent. 

At one time there were thought to be two separate hormones, cholecystokinin which produced contraction of the gall bladder and pancreozymin which increased the secretion of pancreatic enzymes. However it is now known that a single hormone secreted by the upper small intestine performs both activities. 

An in vivo test for the assessment of pancreatic function which consists of giving secretin (which stimulates pancreatic bicarbonate production) and cholecystokinin-pancreozymin (which stimulates the secretion of pancreatic enzymes). Pancreatic fluid is collected and analysed for bicarbonate and one of the pancreatic enzymes (trypsin, amylase or lipase). Low outputs occur in pancreatic disease. 

Trypsin can also be measured in duodenal juice after pancreatic stimulation by secretin-pancreozymin or by a test meal, e.g. as in the Lundh test (q.v.). A deficient output of trypsin is suggestive of pancreatic disease. 

The secretory organ apparently most sensitive to caerulein was the pancreas In the anaesthetized dog)the threshold intravenous dose which stimulated the pancreatic secretion weis 2 to 5 ng/kg)While the threshold subcutaneous dose was 100 ng/ g Doses as low eis 0 3 to 0 6 ng/kg/min were effective by intravenous infusion This dosage is probably of the same magnitude as that active on the gsdl bladder. Unlike the juice ixroduced by secretin but like that produced by pancreozymin the juice yielded by caerulein was rich in enzymes and dry residue ... 

Caerulein is a decapeptide isolated from the skin of the Aus-straliaifrog Hyla caerulea (l). The determination of the amino-acid sequence and subsequent synthesis have been carried out in these laboratories (2). According to Erspamer et al. (3) this pe tide causes a long-lasting blood pressure fall and has gastrin and pancreozymin-like activities on gall bladder motility and on gastric and pancreatic secretions. In the dog, caerulein stimulates external pancreatic secretion at doses as low as 3-6 ng/kg i. v. and decreases blood pressure at doses of 10-100 ng/kg i. v. 

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