Elevated dietary protein intake impairs the renal hemodynamic response to hyperaminoacidemia in patients with primary glomerular diseases.
We have evaluated the renal hemodynamic response to a mixed amino acid infusion in 7 control subjects and in 8 patients with primary glomerulonephritis (GN). In order to evaluate the role of dietary protein intake in this response, GN patients were maintained for 3 weeks on two separate dietary regimens providing 130 +/- 5 g of protein/day (study 1) and 60 +/- 3 g of protein/day (study 2), respectively. Normal subjects were studied while consuming a free diet. In GN patients, following the reduction in dietary protein intake basal RPF and GFR decreased from 589 +/- 109 to 422 +/- 81 ml/1.73 m2/min (p less than 0.01, vs. study 1) and from 75 +/- 7 to 70 +/- 8 ml/1.73 m2/min (p = NS). Filtration fraction rose from 0.14 +/- 0.02 to 0.19 +/- 0.03 (p less than 0.05). In study 1, during amino acid infusion GFR and RPF did not change significantly from baseline (75 +/- 7 vs. 66 +/- 8 ml/1.73 m2/min at 180 min and 589 +/- 109 vs. 567 +/- 102 ml/1.73 m2/min, respectively). These results are at variance with data obtained in normal controls in whom both GFR and RPF rose significantly following hyperaminoacidemia. In contrast, when dietary protein intake was reduced, a normal renal hemodynamic response to amino acid infusion was restored (GFR went from 70 +/- 8 to 90 +/- 18 ml/1.73 m2/min and RPF from 422 +/- 81 to 517 +/- 90 ml/1.73 m2/min, both p less than 0.05 vs. basal), both absolute and percentage increases were similar to what was observed in controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Castellino
P
P
Istituto di Medicina Interna e Nefrologia, I Facoltà di Medicina e Chirurgia, Università di Napoli, Italia.
Cirillo
D
D
Casiere
D
D
Pluvio
C
C
Ciacci
C
C
Giordano
M
M
Pluvio
M
M
Torella
R
R
Coppola
S
S
Giordano
C
C
D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D004044:Dietary Proteins / Q000008:administration & dosage*; D004573:Electrolytes / Q000378:metabolism; D005919:Glomerular Filtration Rate / Q000187:drug effects / Q000502:physiology; D005921:Glomerulonephritis / Q000178:diet therapy / Q000503:physiopathology*; D006728:Hormones / Q000097:blood; D006801:Humans; D008297:Male; D009584:Nitrogen / Q000652:urine; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000502:physiology
D000596:Amino Acids; D001786:Blood Glucose; D004044:Dietary Proteins; D004573:Electrolytes; D006728:Hormones; D009584:Nitrogen