Abstract
Helodermin, a newly isolated peptide from Gila Monster venom, is structurally related to VIP and secretin. When used as radioligand, [125I]helodermin bound rapidly and reversibly to crude rat liver membranes, the dissociation being accelerated by GTP. Competition binding curves of [125I]helodermin and [125I]VIP with unlabelled peptides showed the following order of decreasing affinity: VIP greater than helodermin greater than secretin greater than hpGRF(1-29)-NH2. The shape of binding curves and of concurrent adenylate cyclase activation is compatible with the specific labelling, by [125I]helodermin, of a class of high-affinity VIP receptors that is capable to stimulate adenylate cyclase.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenylyl Cyclases / metabolism
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Animals
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Binding, Competitive
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Cell Membrane / metabolism
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Enzyme Activation
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Growth Hormone-Releasing Hormone / metabolism
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Guanosine Triphosphate / pharmacology
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Intercellular Signaling Peptides and Proteins
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Liver / metabolism*
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Lizards
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Male
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Peptide Fragments / metabolism
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Peptides / metabolism*
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Rats
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Receptors, Cell Surface / metabolism*
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Receptors, Vasoactive Intestinal Peptide
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Secretin / metabolism
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Sermorelin
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Time Factors
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Vasoactive Intestinal Peptide / metabolism
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Venoms / metabolism*
Substances
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Intercellular Signaling Peptides and Proteins
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Peptide Fragments
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Peptides
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Receptors, Cell Surface
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Receptors, Vasoactive Intestinal Peptide
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Venoms
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Secretin
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Vasoactive Intestinal Peptide
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Guanosine Triphosphate
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Sermorelin
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heliodermin
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Growth Hormone-Releasing Hormone
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Adenylyl Cyclases