Measurement of renin and prorenin in cattle, hog and horse.

1. Species specific problems complicating the measurement of prorenin and renin concentrations were studied in bovine, hog and horse plasma. 2. In contrast to horse renin, bovine and hog renin reacted with rat angiotensinogen, allowing measurement of the plasma renin concentration in cattle and hog with rat angiotensinogen as exogenous substrate. 3. Trypsin treatment of plasma in order to activate prorenin generated an interfering angiotensin I immunoreactive material in all three species, most extensively in horse plasma. 4. This material could be removed in bovine and hog plasma by a cation-exchange resin, allowing an assay of the plasma prorenin concentration to be constructed in these species. 5. Another strategy has to be followed in order to measure prorenin and renin concentrations in horse plasma.