Metabolism of arginine by the isolated perfused rat kidney

1978 ◽  
Vol 235 (4) ◽  
pp. F376-F380 ◽  
Author(s):  
G. O. Perez ◽  
M. Epstein ◽  
B. Rietberg ◽  
R. Loutzenhiser
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Sprague Dawley ◽  
Bicarbonate Buffer ◽  
Net Production ◽  
Isolated Perfused Rat Kidney ◽  
Guanidine Derivatives ◽  
Sprague Dawley Rats ◽  
Perfused Rat Kidney ◽  
Guanidinosuccinic Acid

In order to evaluate the renal contribution to the metabolism of arginine, we have evaluated its biosynthesis and catabolism in the isolated perfused rat kidney. The kidneys of eight male Sprague-Dawley rats were perfused with Krebs-Ringer-bicarbonate buffer containing albumin and amino acids. Twenty-five muCi of L-[guanidino-14C]arginine or 25 muCi L-[guanidino-14C]citrulline were added to the system and radiochromatograms of the perfusate were obtained at 0, 30, 60, and 90 min. Perfusate levels of urea, creatine, and guanidine derivatives were measured with high-pressure liquid chromatography. During perfusion there was net utilization of arginine and net production of creatine, guanidinoacetic acid (GAA) and guanidinosuccinic acid (GSA). The guanidino carbon of arginine was incorporated by the kidney into urea, creatine GSA, GAA, and guanidinobutyric acid. The production of 14C-labeled urea from L-[guanidino-14C]citrulline was substantially lower than that previously demonstrated in the liver, while that of arginine was approximately 20 times greater. These studies demonstrate the important contribution of the kidney to the synthesis and metabolism of arginine.

scholarly journals Metabolism of glycine- and hydroxyproline-containing peptides by the isolated perfused rat kidney

1985 ◽  
Vol 229 (2) ◽  
pp. 545-549 ◽  
Author(s):  
M Lowry ◽  
D E Hall ◽  
J T Brosnan
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Isolated Perfused Rat Kidney ◽  
Perfused Rat Kidney ◽  
Rat Kidneys

Isolated perfused rat kidneys removed considerable quantities of glycyltyrosine, glycylhydroxyproline, tetraglycine and prolylhydroxyproline from the perfusate. The component amino acids are released into the perfusate and, in the case of the glycine-containing peptides, there is increased synthesis of serine. Removal of peptides was more than could be accounted for on the basis of filtration, so antiluminal metabolism is indicated. Metabolism of such peptides by the kidney may contribute to renal serine synthesis in vivo.

Effect of 6-aminonicotinamide on renin release in isolated rat kidney: possible role for the pentose pathway

1985 ◽  
Vol 249 (2) ◽  
pp. F213-F219
Author(s):  
S. G. Rostand ◽  
J. Work
Keyword(s):  
Rat Kidney ◽  
Renin Secretion ◽  
Renin Release ◽  
Sprague Dawley ◽  
Bicarbonate Buffer ◽  
Rate Limiting Step ◽  
Sprague Dawley Rats ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Renin Content ◽  
Pentose Pathway

To study the association between renal renin release and the pentose pathway, we perfused nonfiltering kidneys from Sprague-Dawley rats with Krebs-Ringer bicarbonate buffer containing 5 mM glucose and 14 g/100 ml bovine serum albumin in the presence or in the absence of 0.25 mM 6-aminonicotinamide (6AN), an inhibitor of glucose-6-phosphate dehydrogenase, the rate-limiting step of the pentose pathway. Eleven kidneys perfused in the absence of 6AN had a renin secretion rate of 7.4 +/- 2.2 ng ANG I X min-1 X ml-1. In six kidneys perfused in the presence of 6AN, renin release was depressed to 0.56 +/- 0.24 ng ANG I X min-1 X ml-1. The renal renin content for four control kidneys was 56 +/- 3.3 ng ANG I X mg-1 X h-1 while in four kidneys perfused with 6AN renal renin content was lower, 35 +/- 2.9 ng ANG I X mg-1 X h-1. In the presence of 5 mM lactate, the renin release of eight nonfiltering kidneys was 0.31 +/- 0.06 ng ANG I X min-1 X ml-1. The addition of 6AN did not further depress renin secretion in the presence of lactate. 6-Aminonicotinamide also completely blocked furosemide-stimulated renin release without having any effect on glomerular filtration rate or furosemide-induced natriuresis. However, 6AN did not inhibit stimulation of renin secretion by isoproterenol. We conclude that 6-aminonicotinamide interferes with renin release by nonfiltering kidneys and also inhibits furosemide-stimulated renin release but does not affect beta-adrenergic-stimulated renin secretion. Glucose but not lactate is important for maintaining augmented rates of renin secretion in nonfiltering kidneys. 6-Aminonicotinamide significantly reduced renal renin content in the presence of glucose.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Enhanced reabsorption of bicarbonate and phosphorus by the addition of amino acids in the isolated perfused rat kidney

1985 ◽  
Vol 27 (6) ◽  
pp. 951-953 ◽  
Author(s):  
Norihiko Terao ◽  
Muneya Suzuki ◽  
Yasushi Asano ◽  
Saichi Hosoda
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Isolated Perfused Rat Kidney ◽  
Perfused Rat Kidney

scholarly journals Metabolism of valine and 3-methyl-2-oxobutanoate by the isolated perfused rat kidney

1984 ◽  
Vol 224 (1) ◽  
pp. 109-116 ◽  
Author(s):  
R H Miller ◽  
A E Harper
Keyword(s):  
Amino Acids ◽  
High Activity ◽  
Rat Kidney ◽  
Linear Increase ◽  
Isolated Perfused Kidney ◽  
Isolated Perfused Rat Kidney ◽  
Acid Dehydrogenase ◽  
Perfused Rat Kidney ◽  
Branched Chain ◽  
Perfused Kidney

Metabolism of branched-chain amino and 2-oxo acids was studied in the isolated perfused kidney. Significant amounts of 2-oxo acids were released by perfused kidney with all concentrations of amino acids tested (0.1-1.0 mM each), despite the high activity of branched-chain 2-oxo acid dehydrogenase in kidney. As perfusate valine concentration was increased from 0.2 to 1.0 mM, [1-14C]valine transamination (2-oxo acid oxidized + released) increased roughly linearly; [1-14C]valine oxidation, however, increased exponentially. Increasing perfusate concentration of 3-methyl-2-oxo[1-14C]butanoate from 0 to 1.0 mM resulted in a linear increase in the rate of its oxidation and a rise in perfusate valine concentration; at the same time significant decreases occurred in perfusate isoleucine and leucine concentrations, with corresponding increases in rates of release of their respective 2-oxo acids. Comparison of rates of oxidation of [1-14C]valine and 3-methyl-2-oxo[1-14C]butanoate suggests that 2-oxo acid arising from [1-14C]valine transamination has freer access to the 2-oxo acid dehydrogenase than has the 2-oxo acid from the perfusate. The observations indicate that, when branched-chain amino and 2-oxo acids are present in perfusate at near-physiological concentrations, rates of transamination of the amino and 2-oxo acids by isolated perfused kidney are greater than rates of oxidation.

Validation of a toxicity testing model by evaluating oxygen supply and energy state in the isolated perfused rat kidney

1991 ◽  
Vol 25 (3) ◽  
pp. 195-204 ◽  
Author(s):  
Takano Takehito ◽  
Nakata Kazuyo ◽  
Kawakami Tsuyoshi ◽  
Miyazaki Yoshifumi ◽  
Murakami Masataka ◽  
...  
Keyword(s):  
Oxygen Supply ◽  
Energy State ◽  
Rat Kidney ◽  
Toxicity Testing ◽  
Testing Model ◽  
Isolated Perfused Rat Kidney ◽  
Perfused Rat Kidney

Sepsis induces changes in the expression and distribution of Toll-like receptor 4 in the rat kidney

2006 ◽  
Vol 290 (5) ◽  
pp. F1034-F1043 ◽  
Author(s):  
Tarek M. El-Achkar ◽  
Xiaoping Huang ◽  
Zoya Plotkin ◽  
Ruben M. Sandoval ◽  
Georges J. Rhodes ◽  
...  
Keyword(s):  
Rat Kidney ◽  
Expression Patterns ◽  
Cecal Ligation ◽  
Proximal Tubules ◽  
Microbial Pathogens ◽  
Sprague Dawley ◽  
Renal Vasculature ◽  
Two Photon Microscopy ◽  
Sprague Dawley Rats ◽  
Cellular Signal

Toll-like receptors (TLRs) are now recognized as the major receptors for microbial pathogens on cells of the innate immune system. Recently, TLRs were also identified in many organs including the kidney. However, the cellular distribution and role of these renal TLRs remain largely unknown. In this paper, we investigated the expression of TLR4 in a cecal ligation and puncture (CLP) model of sepsis in Sprague-Dawley rats utilizing fluorescence microscopy. In sham animals, TLR4 was expressed predominantly in Tamm-Horsfall protein (THP)-positive tubules. In CLP animals, TLR4 expression increased markedly in all tubules (proximal and distal), glomeruli, and the renal vasculature. The staining showed a strong apical distribution in all tubules. A moderately less intense cellular signal colocalized partially with the Golgi apparatus. In addition, kidneys from septic rats showed increased expression of CD14 and THP. They each colocalized strongly with TLR4, albeit in different tubular segments. We also imaged the kidneys of live septic animals with two-photon microscopy after fluorescent lipopolysaccharide (LPS) injection. Within 10 min, LPS was seen at the brush border of some proximal tubules. Within 60 min, LPS was fully cytoplasmic in proximal tubules. Conversely, distal tubules showed no LPS uptake. We conclude that TLR4, CD14, and THP have specific renal cellular and tubular expression patterns that are markedly affected by sepsis. Systemic endotoxin can freely access the tubular and cellular sites where these proteins are present. Therefore, locally expressed TLRs and other interacting proteins could potentially modulate the renal response to systemic sepsis.

Aldosterone Effects on Renal Function in the Isolated Perfused Rat Kidney

1979 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
Richard Solomon ◽  
Patricio Silva ◽  
Franklin H. Epstein
Keyword(s):  
Renal Function ◽  
Rat Kidney ◽  
Isolated Perfused Rat Kidney ◽  
Perfused Rat Kidney
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