RADIOIMMUNOASSAY OF ANGIOTENSIN II IN PLASMA
1970; Oxford University Press; Volume: 64; Issue: 1 Linguagem: Inglês
10.1530/acta.0.0640181
ISSN1479-683X
Autores Tópico(s)Pharmacological Effects and Assays
ResumoABSTRACT Specific antibodies were produced in rabbits with val5angiotensin II amid (Hypertensin®, Ciba) attached to succinyl-poly-l-lysine. Hypertensin was labelled with iodine-125 ( 125 I) according to a modified Hunter-Greenwood procedure. Ion exchange chromatography followed by antibody association-dissociation technique was used in the purification of the labelled hormone. The separation between bound and free hormone was performed on Sephadex G-25. Maximum binding of the labelled material to the antibody was achieved within one hour. The equilibrium between bound and free hormone was markedly influenced by temperature. It was found that Hypertensin and ileu 5 angiotensin II exhibited equal immunological activities, whereas ileu 5 angiotensin I displayed less than 1% of the affinity of angiotensin II towards the antibody. For the determination of angiotensin II in plasma, samples were collected in chilled tubes containing EDTA and BAL at pH 5.5, in order to inhibit any possible enzymatic generation and degradation of angiotensin II. Concentration was achieved on a column of Dowex 50W – X2(NH 4 +) resin followed by freeze-drying of the eluate. Dilution of the material obtained behaved as standard angiotensin II in the assay. The recovery of 0.5–10 ng of angiotensin II added to 10 ml of plasma was 85–111%. The normal range for young healthy adults was 2.7 ± 1.4 (sd) ng/100 ml, in agreement with reports by some other groups.
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