Abstract
Blood was obtained from normal subjects, pregnant women and hypertensioe patients at rest, after walk and during receiving diuretics, and plasma renin activity was measured by using radioimmunoassay kits supplied by two commercial sources. In order to get a reliable data, attempts were made to check the possible influences of dilution of plasma, error in making standard curve, variations of the data from kit to kit, error associated with the storage of the test materials and the importance of constant incubation.
In normal subjects, plasma renin activity (PRA) was low at rest and elevated after walk, but no diurenal variation was found. During pregnancy, PRA was apparently elevated but this high value subsided rapidly after delivery. The most of young patients with essential hypertension have normal or slightly high PRA, whereas older patients with essential hypertension have low normal or low PRA. Also, the patients with primary aldosteronism have low PRA. Administration of diuretics elevated PRA in patients with essential hypertension but failed to do so in primary aldosteronism. From the data accumulated, it is concluded that PRA is useful for differentiating sev-eral types of hypertension and for selecting the drugs for hypertension.
