Measurements of urinary kinins by HPLC-radioimmunoassay.

In this paper we describe a method for the individual determination of urinary kinins. Extraction from the urine is performed on an Amberlite CG-50 column and kinins are eluted with formic acid. The samples are further purified and kinins are separated by reversed phase HPLC. Bradykinin and lysylbradykinin are quantified by a sensitive radioimmunoassay capable of detecting 0.1 fmol of either peptide. Procedural losses are monitored by measuring the recovery of [3H]bradykinin and [3H]lysylbradykinin. Simple methods for labeling of bradykinin and lysylbradykinin with tritium are also presented. Recoveries of [3H]bradykinin and [3H]lysylbradykinin from biological material ranged between 77 and 91%. The combination of HPLC with radioimmunoassay makes it possible to determine kinin concentrations of biological samples with a higher sensitivity and greater specificity than previous methods.