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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
6
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pubmed:dateCreated |
1987-4-29
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pubmed:abstractText |
Somatostatin binding to guinea pig pancreatic acinar cell plasma membranes was characterized with an iodinated stable analog of somatostatin 28 (S28): 125I-[Leu8,DTrp22,Tyr25]S28. The binding was highly dependent on calcium ions. In 0.2 mM free Ca2+ medium, binding at 37 degrees C was saturable, slowly reversible and exhibited a single class of high affinity binding sites (KD = 0.05 +/- 0.01 nM, Bmax = 157 +/- 33 fmol/mg protein). Dissociation of bound radioactivity occurred with biphasic kinetics. Rate of dissociation increased when dissociation was measured at a time before equilibrium binding was reached. In 30 nM free Ca2+ medium, binding affinity and maximal binding capacity were decreased by about 4-fold. Decreasing calcium concentrations increased the amount of rapidly dissociating form of the receptor. Somatostatin 14 antagonist, Des AA1,2[AzaAla4-5,DTrp8, Phe12-13]-somatostatin was active at the membrane level in inhibiting the binding. We conclude that using 125I-[Leu8,DTrp22,Tyr25]S28 as radioligand allows us to characterize a population of specific somatostatin receptors which are not different from those we previously described with the radioligand 125I-[Tyr11]-somatostatin. Somatostatin receptors could exist in two interconvertible forms. Calcium ions are an essential component in the regulation of the conformational change of somatostatin receptors.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Iodine Radioisotopes,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Neurotransmitter,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Somatostatin,
http://linkedlifedata.com/resource/pubmed/chemical/Somatostatin,
http://linkedlifedata.com/resource/pubmed/chemical/Somatostatin-28
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pubmed:status |
MEDLINE
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pubmed:issn |
0196-9781
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
7
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
953-9
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:2882495-Animals,
pubmed-meshheading:2882495-Binding, Competitive,
pubmed-meshheading:2882495-Calcium,
pubmed-meshheading:2882495-Cell Membrane,
pubmed-meshheading:2882495-Guinea Pigs,
pubmed-meshheading:2882495-Iodine Radioisotopes,
pubmed-meshheading:2882495-Kinetics,
pubmed-meshheading:2882495-Male,
pubmed-meshheading:2882495-Pancreas,
pubmed-meshheading:2882495-Receptors, Neurotransmitter,
pubmed-meshheading:2882495-Receptors, Somatostatin,
pubmed-meshheading:2882495-Somatostatin,
pubmed-meshheading:2882495-Somatostatin-28
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pubmed:articleTitle |
Characterization of pancreatic somatostatin binding sites with a 125I-somatostatin 28 analog.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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