Differential effects of atrial natriuretic peptide and dopamine on urinary protein excretion in chronic glomerulonephritis.
1. To examine whether or not atrial natriuretic peptide-induced proteinuria simply results from increases in urine flow or glomerular filtration rate, we infused dopamine (1 microgram min-1 kg-1) and alpha-human atrial natriuretic peptide (0.025 microgram min-1 kg-1) into nine patients with chronic glomerulonephritis and nine essential hypertensive patients without renal damage, and compared the effects of the two agents on renal function and urinary protein excretion. 2. In patients with chronic glomerulonephritis, dopamine infusion significantly increased urinary sodium excretion (+59%), renal blood flow (+20%) and creatinine clearance (+14%). However, urinary protein excretion was not changed. Addition of atrial natriuretic peptide to the dopamine infusion further increased urinary sodium excretion and maintained creatinine clearance at the same level. In contrast to the infusion of dopamine alone, atrial natriuretic peptide markedly increased urinary protein excretion (77 versus 229 mg min-1 m2, P less than 0.02). Furthermore, the addition of atrial natriuretic peptide elevated the urinary protein/creatinine ratio (1.55 versus 5.35, P less than 0.05), while dopamine alone did not (1.55 versus 1.45, not significant). 3. In essential hypertensive patients, dopamine and dopamine plus ANP showed renal effects similar to those of chronic glomerulonephritis; however, the urinary excretion of protein was not changed significantly. 4. These results suggest that atrial natriuretic peptide may increase urinary protein excretion mainly by increasing the permeability of the damaged glomeruli to protein rather than by simply increasing urine flow or glomerular filtration. Possible mechanisms underlying the proteinuria-increasing effects of atrial natriuretic peptide are discussed.
Hirata
Y
Y
Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Ishii
M
M
Fukui
K
K
Hayakawa
H
H
Suzuki
E
E
Sugimoto
T
T
Kimura
K
K
Matsuoka
H
H
Sugimoto
T
T
D000328:Adult; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002908:Chronic Disease; D006152:Cyclic GMP / Q000652:urine; D004298:Dopamine / Q000494:pharmacology*; D005919:Glomerular Filtration Rate / Q000187:drug effects; D005921:Glomerulonephritis / Q000652:urine*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000652:urine; D007668:Kidney / Q000187:drug effects*; D008875:Middle Aged; D011507:Proteinuria / Q000139:chemically induced*; D014554:Urination / Q000187:drug effects
D009320:Atrial Natriuretic Factor; D006152:Cyclic GMP; D004298:Dopamine