title: Discovery of a cholecystokinin analogue with partial agonist activity.
abstract: In dispersed acini from guinea pig pancreas, cholecystokinin-(27-32)-amide [CCK-(27-32)-NH2] did not stimulate amylase secretion and inhibited the stimulation caused by CCK-(26-33). In dispersed acini from mouse or rat pancreas, CCK-(27-32)-NH2 stimulated amylase secretion. The stimulation of amylase secretion caused by a maximally effective concentration of CCK-(27-32)-NH2 was less than that caused by a maximally effective concentration of cholecystokinin-(26-33), and in contrast to the action of cholecystokinin-(26-33) supramaximal concentrations of CCK-(27-32)-NH2 did not cause submaximal stimulation of amylase secretion. Dibutyryl cGMP and proglumide each inhibited the stimulation of amylase secretion caused by CCK-(27-32)-NH2. CCK-(27-32)-NH2 inhibited binding of 125I-labeled CCK to mouse and rat pancreatic acini. These results indicate that, in mouse and rat pancreatic acini, CCK-(27-32)-NH2 is a partial agonist and that this partial agonist activity is produced by occupation of the CCK receptor by CCK-(27-32)-NH2.
mesh_terms: D000681:Amylases / Q000378:metabolism; D000818:Animals; D002766:Cholecystokinin / Q000302:isolation & purification* / Q000378:metabolism* / Q000494:pharmacology / Q000031:analogs & derivatives; D002851:Chromatography, High Pressure Liquid; D006168:Guinea Pigs; D007457:Iodine Radioisotopes; D008297:Male; D051379:Mice; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011949:Receptors, Cholecystokinin; D013268:Stimulation, Chemical
chemical_list: D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D011949:Receptors, Cholecystokinin; C038242:cholecystokinin (27-32)-amide; D002766:Cholecystokinin; D000681:Amylases