A fluorimetric assay for angiotensin-I converting enzyme in human serum

Carmel, Amos; Ehrlich-Rogozinsky, Sarah; Yaron, Avraham

doi:10.1016/0009-8981(79)90091-3

Cited by 35 publications

(20 citation statements)

References 11 publications

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“…13 The NEP assay was based on a method described by Carvahlo et al 14 The ACE assay is based on the method described by Carmel et al 15 Incubations were carried out in 96-well microplates in triplicate at 4 to 6 concentrations ranging from 100 mol/L to 10 nmol/L. IC 50 was calculated after logit/log transformation of the percentage inhibition data with a best-fit regression model.…”

Section: Methodsmentioning

confidence: 99%

Endothelin-Converting Enzyme Inhibition Ameliorates Angiotensin II–Induced Cardiac Damage

et al. 2002

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Abstract-We tested the hypothesis that endothelin-converting enzyme (ECE) inhibition ameliorates end-organ damage in rats harboring both human renin and human angiotensinogen genes (dTGR). Hypertension develops in the animals, and they die by age 7 weeks of heart and kidney failure. Three groups were studied: dTGR (nϭ12) receiving vehicle, dTGR receiving ECE inhibitor (RO0687629; 30 mg/kg by gavage; nϭ10), and Sprague-Dawley control rats (SD; nϭ10) receiving vehicle, all after week 4, with euthanasia at week 7. Systolic blood pressure was not reduced by ECE inhibitor compared with dTGR (205Ϯ6 versus 206Ϯ6 mm Hg at week 7, respectively). In contrast, ECE inhibitor treatment significantly reduced mortality rate to 20% (2 of 10), whereas untreated dTGR had a 52% mortality rate (7 of 12). ECE inhibitor treatment ameliorated cardiac damage and reduced left ventricular ECE activity below SD levels. Echocardiography at week 7 showed reduced cardiac hypertrophy (4.8Ϯ0.2 versus 5.7Ϯ0.2 mg/g, PϽ0.01) and increased left ventricular cavity diameter (5.5Ϯ0.3 versus 3.1Ϯ0.1 mm, PϽ0.001) and filling volume (0.42Ϯ0.04 versus 0.16Ϯ0.06 mL, PϽ0.05) after ECE inhibitor compared with untreated dTGR. ECE inhibitor treatment also reduced cardiac fibrosis, tissue factor expression, left ventricular basic fibroblast growth factor mRNA levels, and immunostaining in the vessel wall, independent of high blood pressure. In contrast, the ECE inhibitor treatment showed no renoprotective effect. These data are the first to show that ECE inhibition reduces angiotensin II-induced cardiac damage. Key Words: angiotensin II Ⅲ enzymes Ⅲ fibrosis Ⅲ hypertrophy A ngiotensin (Ang) II-related vascular effects are partially mediated by endothelin-1 (ET-1). Long-term Ang II infusion induces preproendothelin mRNA expression. 1 In rats transgenic for both the human renin and human angiotensinogen genes (dTGR), hypertension as well as severe heart and kidney damage develop, largely independent of blood pressure elevation. The rats die by age 7 weeks. 2 The ET-1 A and B (ETA/B) receptor blocker bosentan inhibits the activation of both nuclear factor-kappa B (NF-B) and transcription factor activator protein (AP)-1 in the kidney and the heart, independent of blood pressure reduction in these rats. 3 Bohlender et al 4 studied the same rat strain and showed that a specific ETA receptor blocker is effective, particularly when combined with an Ang II receptor blocker. ET-1 is a 21-amino acid peptide that was first isolated from porcine endothelial cells. 5 Two structurally related peptides differing by 2 (ET-2) and 6 (ET-3) amino acids were subsequently identified. The endothelin precursors are processed by 2 proteases that create mature active forms, termed preproendothelins. The preproendothelins are cleaved at dibasic sites by furin-like endopeptidases to produce inactive intermediates termed big endothelins. Big endothelins are cleaved to form the final products. A family of membrane-bound zinc metalloproteases from the neprilysin superfamily conducts the last...

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Section: Methodsmentioning

confidence: 99%

Endothelin-Converting Enzyme Inhibition Ameliorates Angiotensin II–Induced Cardiac Damage

et al. 2002

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“…ACE levels in samples were calculated from a standard curve run with each assay. ACE activity was measured by fluorometric assay using a fluorescence substrate o-aminobenzoylglycyl-p-nitro-L-phenylalanyl-L-proline (16).…”

Section: Measurement Of Ace Levels and Activitymentioning

confidence: 99%

Mechanism of Increased Angiotensin II Levels in Glomerular Mesangial Cells Cultured in High Glucose

Singh

Singh²,

Alavi³

et al. 2003

Journal of the American Society of Nephrology

138

124

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ABSTRACT. Previous studies have shown that glucose increases angiotensin II (AngII) levels in rat glomerular mesangial cells and that AngII mediates the inhibitory effects of high glucose on matrix degradation in these cells. The present study addresses the following questions: (1) What are the mechanisms for the generation of AngII in mesangial cells? (2) What are the effects of glucose on AngII generation by these mechanisms? Experiments employed primary mesangial cells from normal Sprague-Dawley rats. The levels of immunoreactive angiotensinogen (AGT), angiotensin I (AngI), and angiotensin II (AngII) were measured by ELISA. AGT mRNA expression was determined by Northern blot analysis. Incubation of cells for 24 h in high glucose (30 mM) increased AGT levels by 1.5-fold and increased AGT mRNA expression; this was accompanied by a 1.5-fold increment in AngI and 1.7-fold increment in AngII levels. Renin activity (measured as AngI generation in the presence of excess AGT) and ACE levels and activity were not altered by high glucose. In further experiments, the effect of high glucose on formation of Ang peptides from exogenous AngI in mesangial cell extracts was examined using HPLC. Exogenous AngI was converted into various Ang peptides, including AngII, Ang(1-9), Ang(1-7), and Ang(3-8). A significant increase in formation of AngII from AngI was observed in cells incubated in high glucose. In addition, AngII production from exogenous Ang(1-9) in cell extracts was also stimulated by high glucose. These findings demonstrate that glucose increases mesangial AngII levels via an increase in AGT and AngI. In addition, this study provides new information that Ang(1-9) is produced by mesangial cells, can be converted to AngII, and that this conversion is also stimulated under high-glucose conditions. E-mail: dleehey@lumc.edu

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“…Quantitation of one of the cleavage products, hippuric acid or the dipeptide, has been achieved in a wide variety of ways: spectrophotometric (14,15), fluorimetric (16,17), radioisotopic (18), colorimetric (19)(20)(21), or by HPLC (21)(22)(23). In most assays, a time-consuming extraction procedure is required.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a Test Kit for the Rapid and Simple Colorimetric Measurement of Angiotensin I-Converting Enzyme in Serum

Boomsma¹,

Schalekamp²

1983

CCLM

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Summary:We have evaluated a recently introduced colour test kit for the determination of serum angiotensin I-converting enzyme catalytic activity. p-Hydroxyhippuric acid, liberated from p-hydroxyhippuryl-L-histidyl-L-leucine by angiotensin I-converting enzyme, is cpnverted into a quinoneimine dye with an absorption maximum at 505 nm. The procedure shows excellent linearity over the whole ränge of catalytic activities found in serum. Intra-and inter-assay coefficients of Variation are 2-5 and 7-10% respectively. Correlation with a modified Cushman-Cheung ((1971) Biochem. Pharmacol. 20, 1637-1648) method currently used in our laboratory is good, with r = 0.985 and a regression equation of y (colour kit) = 0.423 (CushmanCheung) + 0.765. Haemoglobin, lipids, bilirubin and prednisone do not interfere but uric acid in concentrations higher than 600 / does. No extraction step is required. The assay is very rapid, and more than twenty samples can be determined in an hour. Bewertende Prüfung eines Testbestecks zur schnellen und einfachen kolorimetrischen Bestimmung von Angiotensin I-Converting Enzyme im Serum

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A fluorimetric assay for angiotensin-I converting enzyme in human serum

Cited by 35 publications

References 11 publications

Endothelin-Converting Enzyme Inhibition Ameliorates Angiotensin II–Induced Cardiac Damage

Endothelin-Converting Enzyme Inhibition Ameliorates Angiotensin II–Induced Cardiac Damage

Mechanism of Increased Angiotensin II Levels in Glomerular Mesangial Cells Cultured in High Glucose

Evaluation of a Test Kit for the Rapid and Simple Colorimetric Measurement of Angiotensin I-Converting Enzyme in Serum

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