title: Radioimmunoassay measurement of thromboxane B2 in human plasma and urine.
abstract: A radioimmunoassay method, using highly specific and sensitive rabbit antiserum, for the measurement of thromboxane (Tx)B2 in human plasma and urine, is described. Assay sensitivity was 5 pg; 50% displacement was achieved by 41 pg of cold TxB. Intra-assay variability was 10% and interassay variability 8,5%. Preliminary extraction and chromatography were necessary as direct radioimmunoassay of plasma although possible, was not reliable. The measurement of TxB2 reflects closely the synthesis of TxA2. The peripheral venous plasma TxB2 concentration in 13 young healthy volunteers (mean age 28 +/- 2 years) was 35 +/- 8 pg/ml; it was significantly higher in 14 older subjects (mean age 45 +/- 5 years) 101 +/- 14 pg/ml (p less than 0.001). Urinary TxB2 excretion was 141 +/- 15 pg/min in the younger group and 220 +/- 39 pg/min in the older group of normotensive subjects. There was a significant positive correlation between urinary TxB2 excretion and age (p less than 0.001). The increase with age of plasma and urinary TxB2 in man may have a pathophysiological importance.
mesh_terms: D000328:Adult; D000375:Aging; D000918:Antibody Specificity; D002845:Chromatography; D005260:Female; D006801:Humans; D007213:Indomethacin; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay / Q000379:methods*; D012016:Reference Values; D013928:Thromboxane A2 / Q000096:biosynthesis; D013929:Thromboxane B2 / Q000097:blood* / Q000276:immunology / Q000652:urine; D013931:Thromboxanes / Q000097:blood*
chemical_list: D013931:Thromboxanes; D013929:Thromboxane B2; D013928:Thromboxane A2; D007213:Indomethacin