Tryptic Activation of Plasma Renin Activity*

Abstract
Trypsinization of human plasma, like acid activation or cryoactivation, increases renin activity, as determined by subsequent enzymatic assay. In three plasma pools, tryptic activation was maximal within 2 min at a trypsin concentration of 500 μg/ml, decreasing athigher concentrations. Neither prolongation of trypsin exposure for up to 1 h nor temperature (0or 37 C) mattered. In plasmas from 26 healthy volunteers ambulatory for 3 h, trypsin increased PRA3-fold from 2.8 ± 0.4 to 8.3 ± 0.7 ng/ml.h(PJ ClinEndocrinol Metab50: 983, 1980)