Nori Sheep Renin ELISA Kit Summary

Alternative names for renin: Angiotensinogenase, REN

Alternative names for sheep: Ovine, lamb, goat, caprine

Standard Curve

Kit Components
1. Pre-coated 96-well Microplate
2. Biotinylated Detection Antibody
3. Streptavidin-HRP Conjugate
4. Lyophilized Standards
5. TMB One-Step Substrate
6. Stop Solution
7. 20 x PBS
8. Assay Buffer

Other Materials Required but not Provided:
1. Microplate Reader capable of measuring absorption at 450 nm
2. Log-log graph paper or computer and software for ELISA data analysis
3. Precision pipettes (1-1000 µl)
4. Multi-channel pipettes (300 µl)
5. Distilled or deionized water

Protocol Outline
1. Prepare all reagents, samples and standards as instructed in the datasheet.
2. Add 100 µl of Standard or samples to each well and incubate 1 h at RT.
3. Add 100 µl of Working Detection Antibody to each well and incubate 1 h at RT.
4. Add 100 µl of Working Streptavidin-HRP to each well and incubate 20 min at RT.
5. Add 100 µl of Substrate to each well and incubate 5-30 min at RT.
6. Add 50 µl of Stop Solution to each well and read at 450 nm immediately.

Background:

Renin is an angiotensinogenase, an enzyme that participates in the body’s renin-angiotensin aldosterone system (RAAS)—also known as the renin-angiotensin-aldosterone axis—that mediates extracellular volume (i.e., that of the blood plasma, lymph and interstitial fluid), and arterial vasoconstriction. Thus, it regulates the body’s mean arterial blood pressure. Renin has an enzymatic activity with which it hydrolyses angiotensinogen to angiotensin I. Mature renin contains 340 amino acids and has a mass of 37 kDa.^[1]  Renin is secreted by the afferent arterioles of the kidney from specialized cells called granular cells of the juxtaglomerular apparatus in response to three stimuli including a decrease in arterial blood pressure, a decrease in sodium levels in the ultrafiltrate of the nephron and sympathetic nervous system activity, which also controls blood pressure, acting through the beta₁ adrenergic receptors. Human renin is secreted by at least 2 cellular pathways: a constitutive pathway for the secretion of prorenin and a regulated pathway for the secretion of mature renin.^[2] Renin can bind to ATP6AP2, which results in a fourfold increase in the conversion of angiotensinogen to angiotensin I over that shown by soluble renin. In addition, renin binding results in phosphorylation of serine and tyrosine residues of ATP6AP2.^[3] An over-active renin-angiotension system leads to vasoconstriction and retention of sodium and water. These effects lead to hypertension. Therefore, renin inhibitors can be used for the treatment of hypertension. ^[4] The plasma renin activity (PRA) is measured specially in case of certain diseases that present with hypertension or hypotension. PRA is also raised in certain tumors. A PRA measurement may be compared to a plasma aldosterone concentration (PAC) as a PAC/PRA ratio. The normal concentration of renin in adult human plasma is 1.98-24.6 ng/L in the upright position. The differential diagnosis of kidney cancer in a young patient with hypertension includes juxtaglomerular cell tumor (reninoma), Wilms’ tumor, and renal cell carcinoma, all of which may produce renin.^[5]

References

1. Imai T, et al. (1983). Proceedings National Academy of Sci USA 80 (24): 7405–9.
2. Pratt RE, et al. (1988) The Journal of Biological Chemistry 263 (7): 3137–41.
3. Nguyen G, et al. (2002) The Journal of Clinical Investigation 109 (11): 1417–27.
4. Ram CV (2009) Future Cardiology 5 (5): 453–65.
5. Méndez GP, et al. (2011) International Journal of Surgical Pathology 19 (1): 93–8.