Abstract
Incubation of human SUP T1 lymphoblasts with VIP, helodermin and related peptides induced homologous desensitization within 5 min as indicated by: 1) a secondary decrease in cellular cyclic AMP levels, even in the presence of phosphodiesterase inhibitors, 2) a reduced capacity of cells to bind [125I]helodermin, 3) decreased helodermin stimulation of adenylate cyclase activity in membranes, and 4) unaffected NaF- and Gpp[NH]p-stimulated adenylate cyclase activities. The desensitizing ability of all peptides correlated with their efficacy to occupy cell receptors, except for [D-Phe2]VIP, a partial VIP agonist with low intrinsic activity, that did not desensitize.
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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1-Methyl-3-isobutylxanthine / pharmacology
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Adenylyl Cyclases / metabolism
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Cell Line
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Cell Membrane / enzymology
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Cyclic AMP / metabolism*
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Guanylyl Imidodiphosphate / pharmacology
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Humans
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Intercellular Signaling Peptides and Proteins
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Kinetics
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Lymphoma
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Peptides / metabolism
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Receptors, Gastrointestinal Hormone / drug effects
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Receptors, Gastrointestinal Hormone / physiology*
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Receptors, Vasoactive Intestinal Peptide
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Vasoactive Intestinal Peptide / metabolism
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Vasoactive Intestinal Peptide / pharmacology*
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Venoms / metabolism
Substances
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Intercellular Signaling Peptides and Proteins
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Peptides
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Receptors, Gastrointestinal Hormone
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Receptors, Vasoactive Intestinal Peptide
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Venoms
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Guanylyl Imidodiphosphate
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Vasoactive Intestinal Peptide
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heliodermin
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Cyclic AMP
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Adenylyl Cyclases
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1-Methyl-3-isobutylxanthine