Radioimmunoassay for Angiotensin-II to be Used in Direct Conjunction with Renin Assay

Abstract

The paper describes details of a radioimmunoassay for angiotensin-II modified to replace the bioassay of angiotensin as used for the estimation of renin in blood. High titre antibodies with association constants of 7 X 10⁹ to 3 X 10¹⁰ l/mole were obtained in rabbits, using carbodiimide condensation of angiotensin-II to γ-globulin. The radioimmunoassay for angiotensin-II is adapted to be performed at the relatively high concentration of plasma found in the plasma pool used for renin assay. Thus, this assay may be carried out directly on the solutions used for renin assay. By adjustment of the method to a high precision, the angiotensin-II formed by the enzyme reactions can be measured to an accuracy of ± 4 % (S. D.).

Key Words:

• Angiotensin-II
• anti-angiotensin-II
• plasma renin concentration
• radioimmunoassay