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Hypertension. 2016 May;67(5):927-33. doi: 10.1161/HYPERTENSIONAHA.115.07012. Epub 2016 Feb 29.

On the Origin of Urinary Renin: A Translational Approach.

Author information

1
From the Division of Pharmacology and Vascular Medicine (L.C.W.R, I.M.G., J.M.G.v.G., A.H.J.D.), Division of Nephrology and Transplantation (L.C.W.R., R.Z., E.J.H.), Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands; Department of Pharmacology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands (B.F.J.H., H.A.J.S.-B.); Department of Physiology and Biophysics, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles (D.N., J. P.-P.); Department of Pharmacology, Kagawa University, Kagawa, Japan (D.N.); and UCL Centre for Nephrology, Royal Free Hospital, London, United Kingdom (S.B.W.).
2
From the Division of Pharmacology and Vascular Medicine (L.C.W.R, I.M.G., J.M.G.v.G., A.H.J.D.), Division of Nephrology and Transplantation (L.C.W.R., R.Z., E.J.H.), Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands; Department of Pharmacology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands (B.F.J.H., H.A.J.S.-B.); Department of Physiology and Biophysics, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles (D.N., J. P.-P.); Department of Pharmacology, Kagawa University, Kagawa, Japan (D.N.); and UCL Centre for Nephrology, Royal Free Hospital, London, United Kingdom (S.B.W.). a.danser@erasmusmc.nl.

Abstract

Urinary angiotensinogen excretion parallels albumin excretion, which is not the case for renin, while renin's precursor, prorenin, is undetectable in urine. We hypothesized that renin and prorenin, given their smaller size, are filtered through the glomerulus in larger amounts than albumin and angiotensinogen, and that differences in excretion rate are because of a difference in reabsorption in the proximal tubule. To address this, we determined the glomerular sieving coefficient of renin and prorenin and measured urinary renin/prorenin 1) after inducing prorenin in Cyp1a1-Ren2 rats and 2) in patients with Dent disease or Lowe syndrome, disorders characterized by defective proximal tubular reabsorption. Glomerular sieving coefficients followed molecular size (renin>prorenin>albumin). The induction of prorenin in rats resulted in a >300-fold increase in plasma prorenin and doubling of blood pressure but did not lead to the appearance of prorenin in urine. It did cause parallel rises in urinary renin and albumin, which losartan but not hydralazine prevented. Defective proximal tubular reabsorption increased urinary renin and albumin 20- to 40-fold, and allowed prorenin detection in urine, at ≈50% of its levels in plasma. Taken together, these data indicate that circulating renin and prorenin are filtered into urine in larger amounts than albumin. All 3 proteins are subsequently reabsorbed in the proximal tubule. For prorenin, such reabsorption is ≈100%. Minimal variation in tubular reabsorption (in the order of a few %) is sufficient to explain why urinary renin and albumin excretion do not correlate. Urinary renin does not reflect prorenin that is converted to renin in tubular fluid.

KEYWORDS:

Dent disease; Lowe syndrome; angiotensinogen; glomerular filtration barrier; renin

PMID:
26928805
PMCID:
PMC4833618
DOI:
10.1161/HYPERTENSIONAHA.115.07012
[Indexed for MEDLINE]
Free PMC Article

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