Properties of vasopressin-activated human platelet high affinity GTPase

• Published in: Biochemical and biophysical research communications Vol. 154; no. 1; pp. 213 - 218
• Main Authors: Vittet, Daniel, Cantau, Bernard, Mathieu, Marie-Noëlle, Chevillard, Claude
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 15.07.1988; Elsevier
• Subjects: Analytical, structural and metabolic biochemistry; Arginine Vasopressin - blood; Arginine Vasopressin - pharmacology; Biological and medical sciences; Blood Platelets - enzymology; Cell Membrane - metabolism; Enzyme Activation; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; GTP Phosphohydrolases - blood; Humans; Hydrolases; Kinetics; Phosphoric Monoester Hydrolases - blood; Receptors, Angiotensin - metabolism; Receptors, Vasopressin; vasopressin; Human; Hormone; DGTPase; Radiolabelling; Peptides; Enzyme; 8-Arginine vasopressin; Molecular interaction; Stimulation; Blood; Proteins; Membrane receptor; Platelet; Enzymatic activity; Plasma membrane; Kinetic parameter
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/0006-291X(88)90672-9

Effect of 8-arginine vasopressin (AVP) was examined on human platelet membrane GTPase activity as an index of a G-protein involvement. AVP stimulated a high-affinity GTPase activity in a dose-dependent manner (K act=1.1±0.2nM). This stimulation was blocked by a V 1a antagonist, thus confirming the V 1a nature of the platelet AVP receptor. There were important variations among individuals in the AVP-induced stimulation of GTPase activity, that were in relation with the AVP-maximal binding capacity. These data suggest a causal relationship between the binding of AVP to its receptor and transduction elicited by a G-protein, without amplification. In addition, in view of the variable AVP responsiveness observed among individuals, platelet AVP-receptor appears to be subject to regulation.