Human platelet fraction arginine-vasopressin. Potential physiological role.
Arginine-vasopressin (AVP) immunoreactivity (Ir) has been found to be elevated in platelet-rich plasma. PlatAVP was defined as platelet-rich plasma Ir minus platelet-poor plasma Ir (Pavp). PlatAVP, Pavp, and synthetic AVP were found to have identical retention time on high performance liquid chromatography analysis and similar mobility on thin-layer chromatography. During a standard osmotic suppression-stimulation test, Pavp increased with plasma osmolality (Posm, mosmol/kg H2O); Pavp (pg/ml) = 0.98 (Posm -274.4), r = 0.57, P less than 0.001, n = 65; but PlatAVP was not significantly correlated with Posm and remained at 5 pg/ml. This PlatAVP concentration was estimated to represent a true intraplatelet AVP concentration of 0.4 to 3.7 X 10(-9) M. Binding studies on intact human platelets demonstrated specific binding sites for [3H]AVP (n = 16; BMax = 98 +/- 30 binding sites/platelet; Kd = 0.72 +/- 0.24 nM). This in vitro affinity association constant (Kd) was close to the estimated in vivo intraplatelet AVP concentration. Measurement of PlatAVP could estimate vasopressin bound to a specific platelet receptor.
D000328:Adult; D001127:Arginine Vasopressin / Q000097:blood*; D001769:Blood; D001792:Blood Platelets / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D003919:Diabetes Insipidus / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D009994:Osmolar Concentration; D011945:Receptors, Angiotensin / Q000378:metabolism; D017483:Receptors, Vasopressin; D012965:Sodium Chloride; D014867:Water
D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D014867:Water; D001127:Arginine Vasopressin; D012965:Sodium Chloride