Measurement of renin activity in plasma by a radio-immunoassay for angiotensin I

Hollemans, H. J. G.; Meer, Jan van der; Kloosterziel, W.

doi:10.1016/0009-8981(69)90105-3

Cited by 41 publications

(12 citation statements)

References 7 publications

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“…To the 500 ul plasma were added 450 ul 0.1M phosphate buffer pH 6.5 and 50 ul of an inhibitor mixture containing 3.3 mg disodium EDTA, 0.6 mg 8 OH quinoline sulphate and 0.6 mg dimercaprol (BAL). This combination of inhibitors has been shown to block angiotensinase activity and converting enzyme activity during incubation of human plasma in vitro (9) and was confirmed to be effective in the present study on rat plasma. were mixed with 450 yd 0.1M phosphate buffer pH 6.5 and 50 \i\ of the inhibitor mixture.…”

Section: Radioimmunoassay Of Angiotensin Isupporting

confidence: 82%

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Measurement of Renin Activity, Concentration and Substrate in Rat Plasma by Radioimmunoassay of Angiotensin I

1972

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The measurement of renin activity, concentration, and substrate in rat plasma has been performed by radioimmunoassay of the angiotensin I generated during incubation of plasma in vitro. The sensitivity of the method permits measurements of all three renin parameters in small plasma samples, allowing sequential determinations to be performed in individual animals. The specificity of the method has been demonstrated by the complete absence of renin in plasma from nephrectomized male rats, by the identical assay slopes of generated angiotensin and angiotensin I standards, and by the parallel changes in plasma renin activity (PRA) and renin concentration (PRC) measured by bioassay and immunoassay after furosemide administration and water deprivation. Also, radioimmunoassay determination of the pH optimum for renin activity, and of the correlations between PRA and PRC, were identical with those obtained by bioassay. The absolute values for renin substrate were similar to those measured by bioassay. However, the values for PRA and PRC measured by radioimmunoassay were higher than those previously observed by bioassay, due to the greater generation of angiotensin I under the incubation conditions employed in the present method. Serial measurement of all three major renin parameters in plasma permits evaluation of the relative contributions of changes in renin secretion and renin substrate to alterations in the activity of the reninangiotensin system during studies in small animals such as the rat. {Endocrinology 90: 422, 1972)

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Section: Radioimmunoassay Of Angiotensin Isupporting

confidence: 82%

“…Radioimmunoassays for angiotensin I have recently been applied to the measurement of PRA in man, giving results which appear to correlate well with those obtained by bioassay (7,8,9). As radioimmunoassay of Received August 11, 1971.…”

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confidence: 81%

Measurement of Renin Activity, Concentration and Substrate in Rat Plasma by Radioimmunoassay of Angiotensin I

1972

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“…Experiments were first performed on renin before and after affinity chromatography on a wide pH gradient (3)(4)(5)(6)(7)(8)(9)(10). Both preparations yielded a single renin peak with an isoelectric point of 4.8 before and 5.0 after affinity chromatography.…”

Section: Characterization Of Purified Reninmentioning

confidence: 99%

Partial Characterization of Hog Renin Purified by Affinity Chromatography

Devaux

Ménard

Sicard³

et al. 1976

Eur J Biochem

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A method has been set up to purify renin on a large scale by affinity chromatography using Pepstatin, a potent inhibitor of renin, as a ligand. Pepstatin was covalently coupled to Sepharose via six different spacer 'arms'. The Sepharose-hexamethylenediamino-Pepstatin appeared to be the better derivative for renin purification even at a concentration as low as 160 nmol of Pepstatinlml of moist gel. Renin was extracted from 100 kg of hog kidneys and semi-purified by ammonium sulfate precipitations and chromatography on DEAE-cellulose. The active fraction (48.5 g of proteins) was applied on a 500-ml affinity column. Renin was eluted in the starting buffer containing6 M urea. Renin was purified 120-fold by the affinity chromatography step with a 79 o/, recovery. Physico-chemical characterization of highly purified renin was performed. Isoelectrofocusing on a pH gradient from 3 to 6 showed a major peak with an isoelectric point (pl) of 4.95 and a minor peak ( p l = 4.70). Polyacrylamide gel electrophoresis, pH 7.8, at different gel concentrations, showed a single peak of renin activity which was found in the major protein band. Molecular size estimated on agarose-acrylamide gel filtration was 40 000. All these physical parameters were similar before and after purification.

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“…PRA-levels were determined by an in-house angiotensin I (Ang I) radioimmunoassay kit 18 and the results are expressed as ng Ang I generated at 37ºC per ml plasma per hour (ng/ml/hour). PRA levels were measured in a separate experiment, which was performed exactly as the simulationexperiment described above.…”

Section: Plasma Renin Activity Measurementsmentioning

confidence: 99%

Involvement of the AT2-receptor in angiotensin II-induced facilitation of sympathetic neurotransmission

Balt

Mathy

Nap

et al. 2002

J Renin Angiotensin Aldosterone Syst

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Angiotensin II (Ang II) causes facilitation of sympathetic neurotransmission via prejunctionallylocated AT 1 -receptors. The pithed rat is a suitable model to study the interactions between endogenously produced Ang II and the sympathetic nervous system at the peripheral level. Previously, we demonstrated that inhibition of the facilitatory actions of Ang II is a class effect of all AT 1 -receptor blockers (ARB). However, all ARBs caused less than maximal inhibition after the highest dose, thus causing a U-shaped dose-response curve with respect to sympatho-inhibition. In the present study, we investigated whether the AT 2 -receptor is involved in this 'upturn' of the dose-response relationship. Accordingly, we studied the effect of the ARB, irbesartan (1-60 mg/kg), on the sequelae of electric stimulation of the thoraco-lumbar sympathetic outflow in the presence and absence of the AT 2 -blocker, PD 123319 (0.5 mg/kg +50 µg/kg/min). Additionally, the effect of the combined (nonselective) AT 1 /AT 2 -receptor antagonist saralasin (0.001, 0.003, 0.01 or 0.03 mg/kg/min), on stimulation-induced responses was studied. In addition, we measured PRA-levels after administration of irbesartan, in this model.The stimulation-induced increase in diastolic blood pressure (DBP) could be dose-dependently reduced by irbesartan. Co-infusion with PD 123319 increased the sympatho-inhibitory potency of irbesartan, possibly through displacement of irbesartan from plasma protein binding sites. The U-shaped dose-response relationship observed with irbesartan, which is illustrative for other ARBs in this model, was not observed when PD 123319 was co-administered with irbesartan, nor with the non-selective AT 1 /AT 2 -blocker, saralasin. PRA-levels increased from 111.0+17.8 to 198.7+22.2 ng/ml/hour after administration of irbesartan. PRA-levels did not differ when measured after the three highest doses of irbesartan. ConclusionsThe present findings indicate a facilitatory role for the AT 2 -receptor, which is unmasked by the highest dose of irbesartan. Different plasma Ang II-levels are unlikely to have caused the less than maximal inhibition after the highest dose of irbesartan.

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Measurement of renin activity in plasma by a radio-immunoassay for angiotensin I

Cited by 41 publications

References 7 publications

Measurement of Renin Activity, Concentration and Substrate in Rat Plasma by Radioimmunoassay of Angiotensin I

Measurement of Renin Activity, Concentration and Substrate in Rat Plasma by Radioimmunoassay of Angiotensin I

Partial Characterization of Hog Renin Purified by Affinity Chromatography

Involvement of the AT2-receptor in angiotensin II-induced facilitation of sympathetic neurotransmission

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