Studies on Mechanisms of Proteinuria Using Amino-Acid-Induced Inhibition of Tubular Reabsorption in Normal and Diabetic Man

2015 ◽  
pp. 50-65 ◽  
Author(s):  
Carl Erik Mogensen ◽  
Karsten S�lling ◽  
Erik Vittinghus
Keyword(s):  
Amino Acid ◽  
Tubular Reabsorption

Renal Handling of Dibasic Amino Acids and Cystine in Cystinuria

1977 ◽  
Vol 53 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Tomoaki Kato
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transport System ◽  
Tubular Reabsorption ◽  
Arginine Infusion ◽  
Amino Acid Infusion ◽  
Control Subjects ◽  
Substrate Concentrations ◽  
Filtered Load ◽  
Dibasic Amino Acids

1. The effect of intravenous infusion of l-lysine and l-arginine on the tubular reabsorption of dibasic amino acids and cystine was studied in normal individuals and in homozygous and heterozygous subjects with cystinuria. 2. The control subjects reabsorbed almost all filtered lysine and arginine until the filtered load was elevated about fourfold. With further increased loads the tubular reabsorption began to fall and tended to approach a maximum reabsorption rate. By contrast, the homozygous subjects could not reabsorb the elevated amino acid beyond the endogenous capacity until the filtered load was increased seven- to ten-fold. When the filtered load was further increased, tubular reabsorption proceeded at the normal rate in the cystinuric patients. 3. These findings may be explained by a low-capacity transport system, which acts at low substrate concentrations, being defective in the cystinuric subjects, while a high-capacity transport system, which predominates at high substrate concentrations, remains intact. 4. Lysine and arginine infusion depressed the percentage tubular reabsorption of other dibasic amino acids and cystine both in the control and the cystinuric subjects. In the control subjects the amino acid infusion caused a gradual linear fall in the fractional reabsorption of the dibasic amino acids and cystine, whereas the depressed reabsorption of the dibasic amino acids in the cystinuric patients returned to that observed under the endogenous condition when the filtered load was high. The amino acid load caused only a gradual decrease in cystine reabsorption in the cystinuric patients. 5. In the heterozygous subjects the slope of the titration curves and the depression of the tubular reabsorption were intermediate between those of the control and homozygous subjects.

Tubular Reabsorption of Amino Acids in the Kidney

Physiology ◽  
1986 ◽  
Vol 1 (5) ◽  
pp. 167-171
Author(s):  
S Silbernagl
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Tubular Reabsorption ◽  
Renal Reabsorption ◽  
Tubular Lumen ◽  
Better Than

Any news about renal reabsorption of amino acids? Today we understand tubular amino acid reabsorption much better than we did 10 years ago. The news about amino acids reported here includes the reabsorption of dipeptides and also the digestion of oligopeptides within the tubular lumen and subsequent absorption of the free constituent amino acids.

Effect of Various Amino Acids on the Renal Tubular Reabsorption of Inorganic Sulfate in the Dog

1956 ◽  
Vol 185 (3) ◽  
pp. 539-542 ◽  
Author(s):  
Fredrik Berglund ◽  
William D. Lotspeich
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Tubular Reabsorption ◽  
Acid Inhibition ◽  
Maximal Rate ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular ◽  
Inorganic Sulfate

Various amino acids depress the sulfate-Tm in the dog. The effects of l-alanine, glycine, d-alanine and l-arginine are compared. The capacity of any one of these amino acids to depress sulfate-Tm correlates directly with maximal rate of reabsorption of the amino acid. The nature of the amino acid inhibition, its relation to amino acid reabsorption, the amino-acidurias and some general problems of renal tubular reabsorption are discussed.

CHARACTERISTICS OF ACIDIC AMINO ACID TRANSPORT IN MAMMALIAN KIDNEY

1963 ◽  
Vol 41 (1) ◽  
pp. 131-137 ◽  
Author(s):  
William A. Webber
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Tubular Reabsorption ◽  
Side Chain ◽  
Acid Transport ◽  
Acidic Amino Acid ◽  
Neutral Amino Acids ◽  
Wide Range ◽  
Renal Tubular

A series of clearance experiments on dogs were carried out which were designed to confirm and characterize the renal tubular reabsorption of glutamic and aspartic acids. Tubular reabsorption was measured and found to reach a maximum of about 100 μmole/minute for L-glutamic and L-aspartic acids and a slightly lower level for D-aspartic. Competitive studies using substituted amino acids were performed and three patterns of inhibition of amino acid reabsorption observed. Acidic amino acids inhibited the reabsorption of each other, while neutral amino acids (and an acidic amino acid substituted so as to have a neutral side chain) inhibited the reabsorption of a wide range of other amino acids. Compounds with the amino group or either carboxyl group substituted or absent, but not resembling neutral amino acids, were not inhibitory. There appears to be a specialized mechanism for acidic amino acid transport which probably requires all three functional groups but which may be interfered with by a compound with alpha carboxyl and amino groups and a neutral side chain.

Effects of Phenylalanine Analogues on Renal Tubular Reabsorption of Amino Acids in the Rat

1977 ◽  
Vol 53 (4) ◽  
pp. 355-364
Author(s):  
C. W. I. Owens
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Concentrations ◽  
Tubular Reabsorption ◽  
Urinary Flow ◽  
Serial Determination ◽  
Forced Diuresis ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular

1. A method is described for the serial determination of renal tubular reabsorption of amino acids in the ethanol-anaesthetized rat. It utilizes intravenous radio-labelled inulins, automated amino acid analysis and forced diuresis. 2. Intravenous loading with phenylalanine and infusion of phenylalanine analogues in this preparation decrease reabsorption of endogenous amino acids in accordance with existing concepts of amino acid transport. 3. Maximal tubular reabsorption (Tmax.) could not be demonstrated for phenylalanine at plasma concentrations below 9 mmol/l. 4. Infusion of phenylalanine analogues into phenylalanine-loaded (‘phenylketonuric’) rats did not specifically inhibit tubular reabsorption of phenylalanine and it is unlikely that any of the substances tested have a potential therapeutic use in man. 5. p-Guanidino derivatives of phenylalanine, in contrast to p-amino derivatives, appear to cause a dose-related basic aminoaciduria. 6. Consideration of urinary flow rates and sodium excretion suggests that the ethanol anaesthesia does not modify amino acid reabsorption through effects on sodium transport or antidiuretic hormone.

CHARACTERISTICS OF ACIDIC AMINO ACID TRANSPORT IN MAMMALIAN KIDNEY

1963 ◽  
Vol 41 (1) ◽  
pp. 131-137 ◽  
Author(s):  
William A. Webber
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Tubular Reabsorption ◽  
Side Chain ◽  
Acid Transport ◽  
Acidic Amino Acid ◽  
Neutral Amino Acids ◽  
Wide Range ◽  
Renal Tubular

A series of clearance experiments on dogs were carried out which were designed to confirm and characterize the renal tubular reabsorption of glutamic and aspartic acids. Tubular reabsorption was measured and found to reach a maximum of about 100 μmole/minute for L-glutamic and L-aspartic acids and a slightly lower level for D-aspartic. Competitive studies using substituted amino acids were performed and three patterns of inhibition of amino acid reabsorption observed. Acidic amino acids inhibited the reabsorption of each other, while neutral amino acids (and an acidic amino acid substituted so as to have a neutral side chain) inhibited the reabsorption of a wide range of other amino acids. Compounds with the amino group or either carboxyl group substituted or absent, but not resembling neutral amino acids, were not inhibitory. There appears to be a specialized mechanism for acidic amino acid transport which probably requires all three functional groups but which may be interfered with by a compound with alpha carboxyl and amino groups and a neutral side chain.

Homoarginine in Cystinuria

1974 ◽  
Vol 46 (2) ◽  
pp. 173-182 ◽  
Author(s):  
B. D. Cox ◽  
J. S. Cameron
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Normal Subjects ◽  
Tubular Reabsorption ◽  
Acid Transport ◽  
Normal Individuals ◽  
Ninhydrin Reaction ◽  
Proximal Tubular ◽  
Health And Disease ◽  
Proximal Tubular Reabsorption

1. By using ion-exchange columns coupled to a sensitive automated Sakaguchi reaction, in addition to the normal ninhydrin reaction for amino acids, homoarginine, a guanidino homologue of arginine, was found in the plasma and urine of both normal and cystinuric individuals. 2. In all seven cystinuric subjects studied, urinary excretion of homoarginine was approximately ten times that found in normal subjects; the plasma levels of this amino acid were considerably reduced relative to normal individuals. 3. Homoarginine in the plasma can be derived either metabolically from lysine or from dietary sources. 4. In normal subjects homoarginine was cleared at a higher rate than arginine. On the other hand, the clearance of arginine exceeded that for homoarginine in the majority of cystinuric subjects although the values obtained for homoarginine indicate that the defect in amino acid transport also affects this amino acid. 5. The defect in the proximal tubular reabsorption of homoarginine is less severe than that for arginine, suggesting that the reabsorptive site for homoarginine may not be the same as that for arginine. 6. In the design of models for the tubular reabsorption of amino acids in health and disease, the presence of homoarginine and its excessive loss in cystinuria must be accounted for.

Role of basolateral cell membranes in organic solute reabsorption in rabbit kidneys

1987 ◽  
Vol 252 (6) ◽  
pp. F1042-F1047
Author(s):  
E. C. Foulkes
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Brush Border ◽  
Tubular Reabsorption ◽  
Cellular Transport ◽  
Organic Solute ◽  
Transport Inhibitors ◽  
Carrier Systems ◽  
Heavy Metal Intoxication

The present work explores the contributions of basolateral carrier systems in tubular reabsorption of organic solutes. Reabsorption of sugars and amino acids, as previously shown, can be represented by a three-compartment linear model that predicts that 1) if basolateral transport contributes to sugar reabsorption, alpha-methylglucoside reabsorption compared with that of glucose should be characterized by a longer transepithelial transit time (TET) and a correspondingly increased cellular transport pool (S), and 2) saturation of basolateral amino acid carriers, or presence of competing amino acids or other basolateral transport inhibitors, should prolong TET of a test amino acid, and increase S above the expected value. Both predictions were fully confirmed. Heavy metal intoxication not only inhibits transport of amino acids at the brush border, but also prolongs their TET and increases the size of S for a given reabsorbed load. Basolateral extrusion of amino acids is more sensitive to metals than is uptake across the brush border. Although basolateral carriers accelerate return of reabsorbed solute to blood, their contribution to reabsorption does not seem to be mandatory.

The staining pattern of the tropomyosin sequence is displayed in a new paracrystal

1986 ◽  
Vol 44 ◽  
pp. 150-151
Author(s):  
M.K. Lamvik ◽  
L.L. Klatt
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Staining Pattern ◽  
Banding Patterns ◽  
Mass Thickness ◽  
New Form

Tropomyosin paracrystals have been used extensively as test specimens and magnification standards due to their clear periodic banding patterns. The paracrystal type discovered by Ohtsuki1 has been of particular interest as a test of unstained specimens because of alternating bands that differ by 50% in mass thickness. While producing specimens of this type, we came across a new paracrystal form. Since this new form displays aligned tropomyosin molecules without the overlaps that are characteristic of the Ohtsuki-type paracrystal, it presents a staining pattern that corresponds to the amino acid sequence of the molecule.

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