Arginine augments neither albuminuria nor albumin synthesis caused by high-protein diets in nephrosis

Abstract

Dietary protein independently modulates albuminuria (U(Alb)V) and albumin synthesis (AlbSyn) in nephrotic rats. While some amino acids are without effect on renal hemodynamics, arginine (Arg) augments renal blood flow and glomerular filtration rate, increases AlbSyn in tissue culture and isolated perfused livers, and could be one specific amino acid causing both decreased glomerular permselectivity and increased AlbSyn. Nephrotic rats were fed 10% casein (LP); 30% casein (HP); 30% casein with the inhibitor of nitric oxide (NO) synthesis N omega-nitro-L-arginine methyl ester (HP + L-NAME); 10% casein supplemented with Arg and amino acids that are Arg precursors of or are derived from Arg (proline, glutamate, and aspartate) in an amount in the increment between 10 and 30% casein (ArgAA); ArgAA supplemented with NH4 acetate to provide a diet isonitrogenous to 30% casein (ArgAA + NH4); or 10% casein plus an incomplete mixture of amino acids (Inc) containing the increment in histidine, phenylalanine, tryptophan, tyrosine, lysine, glycine, alanine, serine, threonine, cysteine, and methionine provided when the diet was changed from 10 to 30% casein. U(Alb)V increased significantly in HP and by a significantly greater amount in HP + L-NAME, but did not change in LP, ArgAA, or ArgAA + NH4. U(Alb)V tended to increase in Inc, was significantly greater than in LP or in ArgAA + NH4, but less than in HP. AlbSyn ([3H]phenylalanine incorporation) was no different in Inc than in HP, and was significantly greater than in either ArgAA + NH4 or LP. Increased AlbSyn results from increased ingestion of one or more of amino acids in Inc, but not from Arg or its precursors or products or from total dietary nitrogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary Protein Restriction and Preservation of Kidney Function in Chronic Kidney Disease

“…This effect is likely mediated by the differences in acid load associated with the two sources of protein sources, although differences in amino acid composition may contribute. We had observed that the effect of increasing dietary amino acid content on urinary protein excretion in nephrotic rats was dependent upon amino acid composition and not total amino acid load [19,20], although the acid content of these diets was not controlled.…”

Nutritional and Non-nutritional Management of the Nephrotic Syndrome

“…In experimental animals however, arginine supplementation actually amliorates both proteinuria and hyperfiltration in diabetic rats, and has no effect on urinary albumin excretion in rats with passive Heymann nephritis [73]. Thus, like the protein-renin interaction outlined above, there are conflicting data regarding the relationship between arginine, its effect on renal hemodynamics, and how that is then translated into alterations in permselectivity.…”

“…In experimental studies in rats, dietary protein augmentation with a mixture of certain amino acids causes a prompt increase in urinary albumin excretion [62], while other amino acids, specifically branch chain amino acids, arginine, proline, glutamine, glutamate, aspartate or asparagine, are devoid of any effect on proteinuria [73]. Studies by D'Amico et al [92] and Walser [93] suggest that dietary protein composition may also be of importance in humans with renal disease.…”

High-Protein Diets Augment Albuminuria in Rats with Heymann Nephritis by Angiotensin II- Dependent and -Independent Mechanisms

“…The fractional renal clearance of albumin increases as well, suggesting that the permselective properties of the glomerular barrier are altered as a consequence of increased dietary protein content [1][2][3] or modified amino acid composition [4,5]. Paller and Hostetter [6] demonstrated that increasing dietary protein increased expression of the renin-angiotensin system in the rat.…”