Simple radioimmunological method for urinary 6-keto-PGF1 alpha measurement

Abstract

A radioimmunoassay for the determination of 6-keto-PGF1 alpha (stable metabolite of Prostacyclin) in urine using a specific antiserum, is described.The antibody used, showed no significant cross-reactivity with other PGS.(3H)-06-keto-PGF1 alpha has been used as tracer and a 30% Hydroxyapatite suspension was utilized for the separation of bound and free fractions.Standard curve ranges between 2 and 1000 pg thus allowing measurements in urine.Aliquots of 0.2 to 1 ml of 24 hours urinary samples were submitted to a preextraction step with Hexane in order to eliminate neutral fats.After acidifying with 0.1 N HCl to pH = 3.5-4, an Ethyl Ether extraction step was performed showing a recovery of 66%.Repeated analysis of a rat urine pool, showed 7.7 intraassay and 9.8 interassay variation coefficients.Values obtained amounted to 38.3 +/- 4.6 ng/24 h in normal rats and 133 +/- 32 ng/24 h in 5% NaCl loaded rats (p less than 0.001).The values obtained in healthy men were 508 +/- 94 ng/24 h and in women 375 +/- 136 (p less than 0.05).