A specific gastrin receptor site in the rat stomach.
A specific receptor for gastrin I has been demonstrated in the rat stomach fundus. Specific binding of 125I-labelled gastrin I was localised to particles sedimenting between 250--20 000 X g. Saturation of binding sites occurred with a gastrin concentration of 10(-11) M in an assay system containing 0.6--1.7 mg/ml of homogenate protein. Gastrin binding was shown to be reversible, temperature- and pH-dependent, and susceptible to tryptic digestion. Electron microscopic and enzymatic studies showed the binding fraction to contain predominantly mitochondria. Preincubation of the homogenate with 10(-8) M cholecystokinin or secretin inhibited gastrin binding to a greater extent than an equimolar concentration of pentagastrin. Cimetidine, a histamine receptor antagonist, did not affect binding of gastrin to the receptor.
D000818:Animals; D002766:Cholecystokinin / Q000494:pharmacology; D002927:Cimetidine / Q000494:pharmacology; D003576:Electron Transport Complex IV / Q000378:metabolism; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D005755:Gastrins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012633:Secretin / Q000494:pharmacology; D013347:Subcellular Fractions / Q000378:metabolism; D013696:Temperature
D005755:Gastrins; D011956:Receptors, Cell Surface; D012633:Secretin; D002927:Cimetidine; D002766:Cholecystokinin; D003576:Electron Transport Complex IV