title: Which urinary proteins are decreased after angiotensin converting--enzyme inhibition?
abstract: It is believed that angiotensin converting-enzyme (ACE) inhibitors lower proteinuria by acting on glomerular hemodynamics. This hypothesis predicts that the urinary excretion of a tubular protein should be unaffected by ACE inhibition. In the present study we have compared the excretion of albumin and Tamm-Horsfall Glycoprotein (THGP), a protein secreted only by renal tubules, before and after ACE inhibition. Urinary protein excretion was measured with the Phast System, a method based on SDS polyacrylamide gel electrophoresis followed by silver staining, in 15 essential hypertensives, after at least 4 weeks of wash-out from any drug and after 2 months of ACE inhibition with oral Quinapril. After 2 months of ACE inhibition, blood pressure (BP), body weight, urinary output, heart rate, plasma glucose, plasma and urinary creatinine, urate and electrolytes, and creatinine clearance, were not different from baseline values. Plasma ACE activity decreased from 76 +/- 7 to 10 +/- 4 U/mL (mean +/- SEM, 2 tails paired t test, p = 0.0001). Both albumin and THP urinary excretions decreased from 51 +/- 6 to 43 +/- 4 mg/ 24 h (p = 0.05) and from 19 +/- 3 to 12 +/- 1 mg/24 h (p = 0.02), respectively. This unexpected result suggests that ACE inhibitors may act also at the level of renal tubular cells.
authors.affiliation: Centro di Ricerca Clinica in Nefrologia e Ipertensine Arteriosa Unità Operativa di Nefrologia Dialisi e Trapianto, Milano, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Guidi
authors.forename: A
authors.initials: A
authors.lastname: Giglioni
authors.forename: M G
authors.initials: MG
authors.lastname: Cozzi
authors.forename: E E
authors.initials: EE
authors.lastname: Minetti
mesh_terms: D000419:Albuminuria / Q000652:urine*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D003404:Creatinine / Q000652:urine; D004573:Electrolytes / Q000652:urine; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000652:urine*; D007546:Isoquinolines / Q000627:therapeutic use*; D008297:Male; D009088:Mucoproteins / Q000652:urine*; D007703:Peptidyl-Dipeptidase A / Q000097:blood; D000077583:Quinapril; D044005:Tetrahydroisoquinolines; D014527:Uric Acid / Q000652:urine; D058949:Uromodulin
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D001786:Blood Glucose; D004573:Electrolytes; D007546:Isoquinolines; D009088:Mucoproteins; D044005:Tetrahydroisoquinolines; C548612:UMOD protein, human; D058949:Uromodulin; D014527:Uric Acid; D003404:Creatinine; D007703:Peptidyl-Dipeptidase A; D000077583:Quinapril