Urinary angiotensin II: a marker of renal tissue activity?

Abstract

The methodology for the collection, extraction, separation and measurement of urinary angiotensin II [the octapeptide, ANG(1-8)] is described. To determine the origin of urinary ANG(1-8), mean arterial pressure, renal hemodynamics and the arterial, renal venous and urinary concentrations of ANG(1-8) were examined prior to and following the constant intra-arterial infusion of tritiated angiotensin II [3H-ANG(1-8)] in graded doses of 0.5, 2.0 and 2.5 ng/kg/min in 5 uninephrectomized, anesthetized female dogs. The infusion of 3H-ANG-(1-8) had no significant effect on mean arterial pressure, glomerular filtration rate, renal blood flow or urine flow rate. The mean concentration of ANG(1-8) in the urine was 3.7 fmol/ml. None or only trace amounts of 3H-ANG(1-8) were detected in the urine in spite of marked increases in renal arterial 3H-ANG(1-8) concentrations. These observations suggest that urinary ANG(1-8) was derived de novo from the intrarenal generation of angiotensin II. In addition, plasma and urinary concentrations of ANG(1-8) were assessed in patients with essential hypertension undergoing treatment with either a diuretic (n = 14) or an angiotensin-converting enzyme inhibitor (n = 14). Although the concentrations of plasma ANG(1-8) responded appropriately to the respective therapies, the urinary excretion of ANG(1-8) was not different following either therapy. These data suggest that ANG(1-8) collected from the urinary bladder may not occur in adequate concentrations to accurately assess the activity of the intrarenal renin-angiotensin system.

• Authors: G Reams, D Villarreal, Z Wu, J H Bauer
• Journal: Nephron (Nephron) Vol. 67 Issue 4 Pg. 450-8 ( 1994) ISSN: 1660-8151 [Print] Switzerland
• PMID: 7969680 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial)

Chemical References

• Angiotensin-Converting Enzyme Inhibitors
• Diuretics
• Tritium
• Angiotensin II

Topics

• Angiotensin II (blood, pharmacology, urine)
• Angiotensin-Converting Enzyme Inhibitors (therapeutic use)
• Animals
• Blood Pressure (physiology)
• Chromatography, High Pressure Liquid
• Diuretics (therapeutic use)
• Dogs
• Dose-Response Relationship, Drug
• Double-Blind Method
• Female
• Glomerular Filtration Rate
• Hemodynamics
• Humans
• Hypertension (blood, drug therapy, urine)
• Kidney (metabolism, physiology)
• Tritium