scholarly journals Activity Assays and Immunoassays for Plasma Renin and Prorenin: Information Provided and Precautions Necessary for Accurate Measurement

2009 ◽  
Vol 55 (5) ◽  
pp. 867-877 ◽  
Author(s):  
Duncan J Campbell ◽  
Juerg Nussberger ◽  
Michael Stowasser ◽  
A H Jan Danser ◽  
Alberto Morganti ◽  
...  
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Inhibitor Therapy ◽  
Renin Activity ◽  
Renin Inhibitor ◽  
Blood Samples ◽  
Hypertensive Patients ◽  
Active Renin ◽  
Open Conformation ◽  
Background Measurement

AbstractBackground: Measurement of plasma renin is important for the clinical assessment of hypertensive patients. The most common methods for measuring plasma renin are the plasma renin activity (PRA) assay and the renin immunoassay. The clinical application of renin inhibitor therapy has thrown into focus the differences in information provided by activity assays and immunoassays for renin and prorenin measurement and has drawn attention to the need for precautions to ensure their accurate measurement.Content: Renin activity assays and immunoassays provide related but different information. Whereas activity assays measure only active renin, immunoassays measure both active and inhibited renin. Particular care must be taken in the collection and processing of blood samples and in the performance of these assays to avoid errors in renin measurement. Both activity assays and immunoassays are susceptible to renin overestimation due to prorenin activation. In addition, activity assays performed with peptidase inhibitors may overestimate the degree of inhibition of PRA by renin inhibitor therapy. Moreover, immunoassays may overestimate the reactive increase in plasma renin concentration in response to renin inhibitor therapy, owing to the inhibitor promoting conversion of prorenin to an open conformation that is recognized by renin immunoassays.Conclusions: The successful application of renin assays to patient care requires that the clinician and the clinical chemist understand the information provided by these assays and of the precautions necessary to ensure their accuracy.

Should blood samples for assay of plasma renin activity be chilled?

1978 ◽  
Vol 24 (11) ◽  
pp. 2042-2043 ◽  
Author(s):  
R L Emanuel ◽  
G H Williams
Keyword(s):  
Plasma Renin Activity ◽  
Room Temperature ◽  
Plasma Renin ◽  
The Other ◽  
Renin Activity ◽  
Angiotensin I ◽  
Blood Samples ◽  
Hypertensive Patients

Abstract Collecting blood on ice for renin determination reportedly may produce falsely high results. To assess the probability of this occurring under actual collection conditions, we measured renin activity in duplicate aliquots of plasma from blood samples from 25 hypertensive patients, both supine and upright, and in 10 supine normotensive controls. One aliquot of the blood was collected on ice and processed at 4 degrees C, the other at room temperature. The two aliquots showed no significant differences in renin activity. If anything, values for samples collected at room temperature were higher. Repeat determination on the same specimens stored at--20 degrees C for nine and 12 months revealed no significant changes in results for any samples, although the amount of angiotensin I found in the sample before incubation at 37 degrees C significantly increased. We conclude that it makes little difference at what temperature one collects blood for renin determination, but because of the wide fluctuations in "room" temperature we recommend that blood samples be collected on ice.

Effect of temperature on plasma renin samples.

1978 ◽  
Vol 24 (7) ◽  
pp. 1202-1204 ◽  
Author(s):  
F Fyhrquist ◽  
L Puutula
Keyword(s):  
Plasma Renin Activity ◽  
Room Temperature ◽  
Plasma Renin ◽  
Renin Activity ◽  
Effect Of Temperature ◽  
Plasma Samples ◽  
Hypertensive Patients ◽  
Variable Extent ◽  
Venous Plasma

Abstract Plasma renin activity was measured in parallel in Na2EDTA-contained plasma samples after storage at -20, 4, and 24 degrees C, and in the lyophilized state. In peripheral venous plasma from 22 hypertensive patients, the activity (range, 0.08-46.7 microgram/liter per hour) remained stable during three days of storage at 4 degrees C, but decreased to a variable extent when plasma was kept at 24 degrees C: in one day by 9.2%, two days by 25.6%, and three days by 74.0%. Values were the same for samples handled at room temperature and chilled to 4 degrees C within 3 h and parallel samples immediately cooled in an icebath and kept at 4 degrees C. Freezing (-20 degrees C) and thawing of plasma was associated with a 22% mean increase in activity (range, 0-83%). Lyophilization resulted in a smaller increase of plasma renin activity (mean 12%, range 0-46%). Blood for renin analysis need not be cooled immediately, but must be cooled to 4 degrees C within 2-3 h. It then is stabe for at least three days. Freezing or lyophilization appears to be associated with some cold activation of "prorenin."

Effect of ovariectomy on vasopressin, ACTH, and renin activity responses to hypotension

1991 ◽  
Vol 261 (1) ◽  
pp. R223-R230 ◽  
Author(s):  
M. Keller-Wood ◽  
C. E. Wood
Keyword(s):  
Plasma Renin Activity ◽  
Arginine Vasopressin ◽  
Adrenocorticotropic Hormone ◽  
Plasma Renin ◽  
Renin Activity ◽  
Plasma Acth ◽  
Blood Samples

The gonadal axis is thought to modulate adrenocorticotropic hormone (ACTH), arginine vasopressin (AVP), and plasma renin activity (PRA) responses to stimuli in several species. These experiments were designed to compare the responses to hypotension in chronically ovariectomized ewes and intact ewes. The ewes were infused with nitroprusside at rates of 5, 10, or 15 micrograms.kg-1.min-1 or infused with vehicle for 10 min. The response to 15 micrograms.kg-1.min-1 was also tested with or without treatment with 10 mg of dexamethasone 2 h before nitroprusside. Blood samples were collected before and at 5, 10, 15, 20, and 30 min after the start of the infusion for measurement of plasma ACTH, AVP, and PRA. In both groups of animals there were significant responses to hypotension. There was a significant effect of ovariectomy on ACTH, AVP, and PRA responses. ACTH and PRA responses were lower in the ovariectomized ewes; AVP responses were increased in the ovariectomized ewes. Administration of dexamethasone inhibited ACTH responses and did not inhibit PRA responses in both groups of ewes. Administration of dexamethasone did not inhibit the AVP response in the intact ewes but did reduce the response in the ovariectomized ewes.

Sodium and Renin in the Hypertension of Early Renal Disease

1978 ◽  
Vol 55 (s4) ◽  
pp. 301s-303s ◽  
Author(s):  
S. F. Wong ◽  
M. I. Mitchell ◽  
V. Robson ◽  
R. Wilkinson
Keyword(s):  
Blood Pressure ◽  
Renal Disease ◽  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Renin Activity ◽  
Exchangeable Sodium ◽  
Hypertensive Patients ◽  
Body Build ◽  
Activity Response ◽  
Normal Controls

1. Plasma renin activity, response to saralasin and exchangeable sodium have been measured in 43 patients with early renal disease. 2. Blood pressure was directly proportional to plasma renin activity. However, mean plasma renin activity was lower in patients with renal disease than in normal controls. 3. Blood pressure fell in response to saralasin infusion in proportion to the pre-infusion plasma renin activity. 4. Exchangeable sodium in hypertensive patients with renal disease did not exceed that in normotensive patients in contrast to earlier reports. Discrepancies may arise from the difficulty in interpreting measured exchangeable sodium in relation to body build.

Plasma Renin in Long-Term Diuretic Treatment of Hypertension: Effect of Discontinuation and Restarting Therapy

1982 ◽  
Vol 63 (2) ◽  
pp. 121-125 ◽  
Author(s):  
S. Swart ◽  
R. F. Bing ◽  
J. D. Swales ◽  
H. Thurston
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Juxtaglomerular Apparatus ◽  
Significant Rise ◽  
Renin Activity ◽  
Hypertensive Patients ◽  
Diuretic Treatment ◽  
Low Renin Hypertension ◽  
Before And After

1. Plasma renin activity, body weight and blood pressure were measured before and after 7 days' treatment with bendrofluazide in ten hypertensive subjects. They were then treated with bendrofluazide alone (5 mg daily) for a minimum of 3 years. The diuretic was then discontinued and the measurements were repeated before and again after 7 days with bendrofluazide. The results were compared with those obtained before chronic treatment with the diuretic. 2. Chronic diuretic treatment was associated with a persistent and progressive rise in plasma renin activity, that fell promptly to pretreatment levels when diuretics were discontinued. This was associated with significant weight gain but no immediate significant rise in blood pressure. 3. When acutely challenged with bendrofluazide the patients showed a greater increase in plasma renin activity on the second occasion than on the first. Three out of five patients with an initially subnormal response had normal responses after chronic diuretic treatment. 4. Chronic diuretic treatment increased the responsiveness of the juxtaglomerular apparatus in some hypertensive patients. 5. Classification of hypertensive patients into renin subgroups may be influenced by previous therapy, even when that therapy has been discontinued for 4 weeks. In particular ‘low renin hypertension’ may be masked by recent use of diuretics, as shown by three of the five patients in this subgroup in the present study.

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