title: Effects of perfusion pressure and renal flow upon albumin excretion in isolated perfused kidneys.
abstract: To explore the effects of renal hemodynamics upon urinary albumin excretion, sequential changes in perfusion pressure and/or flow were performed in isolated perfused rat kidneys. Elevation of perfusion pressure from 90 to 130 mm Hg increased renal flow from 48.9 +/- 1.1 to 54.3 +/- 1.4 ml/min and glomerular filtration rate (GFR) from 0.37 +/- 0.03 to 0.81 +/- 0.06 ml/min (p less than 0.001). Despite more than a doubling in GFR, albumin excretion remained unchanged (from 252 +/- 53 to 167 +/- 36 micrograms/min, p not significant), resulting in a decreased fractional clearance of albumin (theta) from 0.009 +/- 0.002 to 0.004 +/- 0.005 ml/min (p less than 0.01). To dissociate the effects of flow from those of pressure, angiotensin II was infused to decrease renal flow from 49.9 +/- 0.6 to 38.7 +/- 0.6 ml/min (p less than 0.001), while keeping perfusion pressure constant at 96 +/- 1 mm Hg. Although GFR was essentially unchanged (from 0.59 +/- 0.02 to 0.65 +/- 0.05 ml/min, p not significant), albumin excretion increased from 68 +/- 8 to 151 +/- 21 micrograms/min (p less than 0.001) and theta rose from 0.002 +/- 0.000 to 0.005 +/- 0.001 (p less than 0.02). Whole kidney hemodynamics acutely affect renal excretion of albumin in isolated kidneys.
authors.affiliation: Department of Medicine, Hadassah University Hospital, Jerusalem, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Raz
authors.forename: N
authors.initials: N
authors.lastname: Kaminski
authors.forename: M
authors.initials: M
authors.lastname: Brezis
mesh_terms: D000419:Albuminuria / Q000503:physiopathology*; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure; D005919:Glomerular Filtration Rate / Q000187:drug effects; D007678:Kidney Glomerulus / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012044:Regression Analysis; D012079:Renal Circulation / Q000187:drug effects
chemical_list: D000804:Angiotensin II