Cholecystokinin receptors: disparity between phosphoinositide breakdown and amylase releasing activity of CCK analogues in pancreas
Cholecystokinin (CCK) peptides are a family of hormones which also occur in brain. In pancreas CCK stimulates the release of amylase, a process that is dependent on the mobilization of intracellular Ca/sup 2 +/. Recent evidence suggests that inositol 1,4,5-trisphosphate, the breakdown product of phosphatidylinositol 4,5-bisphosphate, is responsible for the rise in intracellular Ca/sup 2 +/. Their laboratory has developed assays to study synthetic CCK analogues using radioligand binding, PI breakdown and amylase release. They have shown that there are good correlations among these three assay systems for the carboxy terminal fragments of CCK/sub 8/. Recently, they have discovered synthetic analogues of CCK/sub 4/ that are full agonists in amylase release but are ineffective in causing PI breakdown. In particular, A-61576, Boc-5-amino-2-indolemethylene-pent-2-ene-1-oyl-Leu-Asp-Phe-NH/sub 2/, is a full agonist in the amylase releasing assay, but is devoid of PI stimulating activity. A-61576 completely reverses the stimulation of PI response induced by CCK/sub 8/, indicative of an antagonist. Since a mechanism other than the PI breakdown is responsible for amylase release by A-61576, they suggest that separate receptors are responsible for PI breakdown and amylase release.
- Research Organization:
- Abbott Labs., Chicago, IL
- OSTI ID:
- 6943119
- Report Number(s):
- CONF-8604222-; TRN: 87-007019
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMYLASE
ENZYME ACTIVITY
KININS
BIOCHEMICAL REACTION KINETICS
RECEPTORS
PHOSPHOLIPIDS
METABOLISM
CALCIUM COMPOUNDS
PANCREAS
TRACER TECHNIQUES
ALKALINE EARTH METAL COMPOUNDS
BODY
DIGESTIVE SYSTEM
ENDOCRINE GLANDS
ENZYMES
ESTERS
GLANDS
GLYCOSYL HYDROLASES
HYDROLASES
ISOTOPE APPLICATIONS
KINETICS
LIPIDS
MEMBRANE PROTEINS
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
REACTION KINETICS
550201* - Biochemistry- Tracer Techniques