Biomaterial Database

Measurement of plasma renin activity as a valid estimation of plasma angiotensin status. 1978

J E Roulston, and G A Macgregor, and T Adam, and N D Markandu

Measurement of plasma renin activity is widely used as an indirect assessment of plasma angiotensin II concentration. There has been some controversy over the validity of this assay as an estimate of circulating angiotensin II levels because, during the in vitro generation of angiotensin I by renin, over a period of time, substrate concentration may diminish to such an extent that it becomes rate-limiting, giving an artificially low reflection of angiotensin II levels. In this paper the initial angiotensin I concentration, that is the concentration before in vitro angiotensin I generation, has been compared with the corresponding plasma renin activity for 2752 individual plasma samples. A linear relationship was found between the initial angiotensin I concentration and the plasma renin activity below 60 ng ml-1 h-1. This indicates that, under the conditions of this assay, substrate does not appear to become rate-limiting except at exceedingly high levels of plasma renin activity. These results appear to provide further validation for the use of plasma renin activity measurement as a reflection of the concentration of circulating angiotensin II levels.

UI	MeSH Term	Description	Entries
D011863	Radioimmunoassay	Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.	Radioimmunoassays
D012083	Renin	A highly specific (Leu-Leu) endopeptidase that generates ANGIOTENSIN I from its precursor ANGIOTENSINOGEN, leading to a cascade of reactions which elevate BLOOD PRESSURE and increase sodium retention by the kidney in the RENIN-ANGIOTENSIN SYSTEM. The enzyme was formerly listed as EC 3.4.99.19.	Angiotensin-Forming Enzyme,Angiotensinogenase,Big Renin,Cryorenin,Inactive Renin,Pre-Prorenin,Preprorenin,Prorenin,Angiotensin Forming Enzyme,Pre Prorenin,Renin, Big,Renin, Inactive
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000803	Angiotensin I	A decapeptide that is cleaved from precursor angiotensinogen by RENIN. Angiotensin I has limited biological activity. It is converted to angiotensin II, a potent vasoconstrictor, after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME.
D000804	Angiotensin II	An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME. The amino acid in position 5 varies in different species. To block VASOCONSTRICTION and HYPERTENSION effect of angiotensin II, patients are often treated with ACE INHIBITORS or with ANGIOTENSIN II TYPE 1 RECEPTOR BLOCKERS.	Angiotensin II, Ile(5)-,Angiotensin II, Val(5)-,5-L-Isoleucine Angiotensin II,ANG-(1-8)Octapeptide,Angiotensin II, Isoleucine(5)-,Angiotensin II, Valine(5)-,Angiotensin-(1-8) Octapeptide,Isoleucine(5)-Angiotensin,Isoleucyl(5)-Angiotensin II,Valyl(5)-Angiotensin II,5 L Isoleucine Angiotensin II,Angiotensin II, 5-L-Isoleucine