Editorial Type:
Analytic Techniques

Measurement of plasma renin concentration in cats by use of a fluorescence resonance energy transfer peptide substrate of renin

Chad W. Schmiedt Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

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 DVM
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Katherine A. E. Hurley Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

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Xiaohe Tong AnaSpec Inc, 34801 Campus Dr, Fremont, CA 94555.

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Vera A. Rakhmanova AnaSpec Inc, 34801 Campus Dr, Fremont, CA 94555.

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Cecilia L. Po AnaSpec Inc, 34801 Campus Dr, Fremont, CA 94555.

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David J. Hurley Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

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DOI:
https://doi.org/10.2460/ajvr.70.11.1315
Volume/Issue:
Volume 70: Issue 11
Online Publication Date:
01 Nov 2009
Restricted access
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Abstract

Objective—To evaluate the use of a commercially available 5-carboxyfluorescein–based, intramolecularly quenched, fluorescence resonance energy transfer (FRET) peptide substrate of renin for measurement of plasma renin concentration in cats.

Sample Population—Plasma samples obtained during a previous study of renal autograft ischemia-reperfusion injury in 10 cats and samples of fetal bovine serum containing recombinant human renin (rh-renin).

Procedures—Experiments involving samples of fetal bovine serum containing rh-renin were conducted to identify a suitable control vehicle, optimal substrate concentration, and appropriate duration of incubation. With the use of the identified assay conditions, a standard curve was constructed to allow conversion of relative fluorescent units into values of renin concentration (ng/mL). Subsequently, plasma samples obtained from cats before and after renal autograft ischemia-reperfusion injury were assayed to determine endogenous renin concentration.

Results—Under conditions of a 1:50 substrate dilution and 4-hour incubation period, the assay detected small amounts of rh-renin in fetal bovine serum. A linear relationship (R2 = 0.996) between the relative fluorescent units generated and exogenous rh-renin concentration was evident. The assay detected renin in plasma samples obtained from cats after renal autograft ischemia-reperfusion, and renin concentrations on days 1 and 2 after transplant differed significantly.

Conclusions and Clinical Relevance—The study data indicated that the assay involving the FRET peptide substrate of renin is potentially a rapid and specific method for measurement of plasma renin concentration in cats.

Abstract

Objective—To evaluate the use of a commercially available 5-carboxyfluorescein–based, intramolecularly quenched, fluorescence resonance energy transfer (FRET) peptide substrate of renin for measurement of plasma renin concentration in cats.

Sample Population—Plasma samples obtained during a previous study of renal autograft ischemia-reperfusion injury in 10 cats and samples of fetal bovine serum containing recombinant human renin (rh-renin).

Procedures—Experiments involving samples of fetal bovine serum containing rh-renin were conducted to identify a suitable control vehicle, optimal substrate concentration, and appropriate duration of incubation. With the use of the identified assay conditions, a standard curve was constructed to allow conversion of relative fluorescent units into values of renin concentration (ng/mL). Subsequently, plasma samples obtained from cats before and after renal autograft ischemia-reperfusion injury were assayed to determine endogenous renin concentration.

Results—Under conditions of a 1:50 substrate dilution and 4-hour incubation period, the assay detected small amounts of rh-renin in fetal bovine serum. A linear relationship (R2 = 0.996) between the relative fluorescent units generated and exogenous rh-renin concentration was evident. The assay detected renin in plasma samples obtained from cats after renal autograft ischemia-reperfusion, and renin concentrations on days 1 and 2 after transplant differed significantly.

Conclusions and Clinical Relevance—The study data indicated that the assay involving the FRET peptide substrate of renin is potentially a rapid and specific method for measurement of plasma renin concentration in cats.

Contributor Notes

Supported by AnaSpec Inc through the donation of material.

Dr. Rakhmanova, Xiaohe Tong, and Cecilia Po are employed by AnaSpec Inc, which manufactures and sells the kit used in this study to evaluate renin activity in cats.

Address correspondence to Dr. Schmiedt (cws@uga.edu).
Cover American Journal of Veterinary Research
American Journal of Veterinary Research
Publication Date:
01 Nov 2009
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