scholarly journals Synthesis of bile acid monosulphates by the isolated perfused rat kidney

1976 ◽  
Vol 156 (2) ◽  
pp. 339-345 ◽  
Author(s):  
J A Summerfield ◽  
J L Gollan ◽  
B H Billing
Keyword(s):  
Bile Acid ◽  
Chenodeoxycholic Acid ◽  
Lithocholic Acid ◽  
Rat Kidney ◽  
Free Medium ◽  
Perfused Rat Kidney ◽  
Free Bile Acid ◽  
Cholestatic Syndrome ◽  
Protein Free Medium ◽  
Isolated Rat

Perfusion of an isolated rat kidney with labelled bile acids, in a protein-free medium, resulted in the urinary excretion of the labelled bile acid, 3% being converted into polar metabolities in 1h. These metabolities were neither glycine nor taurine conjugates, nor bile acid glucuronides, and on solovolysis yielded the free bile acid. On t.l.c. the metabolite of [24-14C]lithocholic acid had the mobility of lithocholate 3-sulphate. The principal metabolite of [24-14C]chenodeoxycholic acid had the mobility of chenodeoxycholate 7-sulphate; trace amounts appeared as chenodeoxycholate 3-sulphate. [35S]sulphate was incorporated in chenodeoxycholic acid by the kidney, resulting in a similar pattern of sulphation. No disulphate salt of chenodeoxycholic acid was detected. These findings lend support to the hypothesis that renal synthesis may account for some of the bile acid sulphates present in urine in the cholestatic syndrome in man.

Acid excretion by bicarbonate-free perfused rat kidney

1981 ◽  
Vol 240 (4) ◽  
pp. F306-F310
Author(s):  
M. H. Garvey ◽  
D. L. Maude
Keyword(s):  
Carbonic Anhydrase ◽  
Rat Kidney ◽  
Acid Excretion ◽  
Total Acid ◽  
Urine Ph ◽  
Titratable Acid ◽  
Perfused Rat Kidney ◽  
Reduced Rate ◽  
Isolated Rat

We measured titratable acid (TA) and NH4 excretion by isolated rat kidneys perfused either with conventional bicarbonate-containing solutions or with solutions in which bicarbonate was replaced by propionate. Rates of TA excretion by bicarbonate-perfused kidneys were similar to in vivo values, 0.27 +/- 0.04 mueq.ml GF-1 (0.21 mueq.min-1.g-1), and increased significantly under bicarbonate-free conditions to 0.70 +/- 0.12 mueq.ml GF-1 (0.42 mueq.min-1.g-1). At the same time the perfusate/urine pH difference (delta pH) increased significantly, from 0.63 +/- 0.06 to 0.92 +/- 0.06. Carbonic anhydrase inhibition by 5 X 10(-4) M acetazolamide alkalinized the urine of bicarbonate-perfused kidneys, while in the bicarbonate-free preparation the urine remained acid (delta pH = 0.27 +/- 0.04) and titratable acid continued to be excreted, though at a reduced rate, 0.19 +/- 0.04 mueq.ml GF-1. Under these same bicarbonate-free carbonic anhydrase-inhibited conditions, lowering the perfusate pH from 7.4 to 7.1 increased delta pH to 0.36 +/- 0.02 and caused total acid excretion (TA + NH4) to rise from 0.29 +/- 0.04 to 0.45 +/- 0.06 mueq.ml GF-1, and increasing the perfusate [HPO4] from 2.4 to 9.6 mM increased TA to 0.80 +/- 0.09 mueq.ml GF-1.

Transamination of branched-chain keto acids by isolated perfused rat kidney.

1978 ◽  
Vol 235 (1) ◽  
pp. E47
Author(s):  
W E Mitch ◽  
W Chan
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Branched Chain Amino Acids ◽  
Keto Acid ◽  
Branched Chain Amino Acid ◽  
Keto Acids ◽  
Perfused Rat Kidney ◽  
Branched Chain ◽  
Branched Chain Keto Acids ◽  
Isolated Rat

Isolated rat kidney perfused without substrate released serine, glycine, and taurine, and substantially smaller amounts of other amino acids. When branched-chain keto acids were added, the corresponding amino acids were released at rates amounting to 15-25% of keto acid disappearance. Perfusion with 2 mM alpha-keto-isovalerate or alpha-keto-beta-methylvalerate caused an increased glucose release amounting to 18-23% of keto acid disappearance. The activity of branched-chain amino acid transferase (BATase) was significantly stimulated by perfusion with the analogue of leucine, but not by perfusion with alpha-ketoglutarate, the analogues of valine or isoleucine, or with leucine itself. These findings document that the kidney converts branched-chain keto acids in part to the corresponding amino acids and suggest that the keto analogue of leucine may be involved in the control of renal BATase activity, thereby indirectly regulating the metabolism of branched-chain amino acids.

Direct release of angiotensins I and II from isolated rat kidney perfused with angiotensinogen-free medium

1987 ◽  
Vol 149 (2) ◽  
pp. 475-481 ◽  
Author(s):  
Kenji Mizuno ◽  
Koichi Higashimori ◽  
Teruaki Imada ◽  
Tadashi Inagami
Keyword(s):  
Rat Kidney ◽  
Free Medium ◽  
Isolated Rat Kidney ◽  
Isolated Rat

scholarly journals The role of tubular reabsorption in the renal excretion of bile acids

1977 ◽  
Vol 166 (1) ◽  
pp. 65-73 ◽  
Author(s):  
S Barnes ◽  
J L Gollan ◽  
B H Billing
Keyword(s):  
Bile Acids ◽  
Renal Excretion ◽  
Rat Kidney ◽  
Tubular Secretion ◽  
Tubular Reabsorption ◽  
Free Medium ◽  
Proximal Tubular ◽  
Protein Free Medium ◽  
Conjugated Bilirubin

1. The renal excretion of bile acids was studied in an isolated rat kidney preparation perfused with a protein-free medium. 2. Tubular reabsorption exceeded 95% for both non-sulphated and sulphated bile acids at filtered loads of less than 30 nmol/min. 3. At low filtered loads the reabsorption of taurocholate and taurochenodeoxycholate was almost complete. Efficient reabsorption of taurochenodeoxycholate was maintained over a wider range of filtered loads than for taurocholate. These observations suggest that active transport may occur. 4. At high filtered loads saturation of reabsorption of taurocholate and taurochenodeoxycholate did not occur, which indicates that passive diffusion is involved in reabsorption. 5. Active proximal-tubular secretion of bile acids was not demonstrated in competition experiments with p-aminohippurate. 6. The fractional reabsorption of taurocholate, chenodeoxycholate 3,7-disulphate and chenodeoxycholate 7-monosulphate was decreased by the addition of taurochenodeoxycholate to the perfusate, so that their renal excretion was enhanced. This interaction between the bile acids for reabsorption may explain the different composition of bile acids in urine compared with that in plasma in cholestasis in man. 7. Conjugated bilirubin decreased the fractional reabsorption of both taurocholate and taurochenodeoxycholate at low filtered loads (less than 30 nmol/min) but not at high filtered loads (400 nmol/min).

Glutamine synthesis in the perfused rat kidney and in isolated rat cortical tubules: regulation by pH

1985 ◽  
Vol 69 (6) ◽  
pp. 701-707 ◽  
Author(s):  
Henri Lanctin ◽  
John T. Brosnan ◽  
Brian D. Ross
Keyword(s):  
Metabolic Acidosis ◽  
Isotope Dilution ◽  
Rat Kidney ◽  
Ammonia Excretion ◽  
Ammonia Production ◽  
Dilution Technique ◽  
Isotope Dilution Technique ◽  
Perfused Rat Kidney ◽  
Glutamine Synthesis ◽  
Isolated Rat

1. The possible involvement of renal glutamine synthesis in the regulation of ammoniagenesis during metabolic acidosis has been investigated. 2. Using an isotope dilution technique glutamine synthesis has been demonstrated in the intact perfused rat kidney, despite zero net balance for glutamine in this preparation. 3. Inhibition of glutamine synthesis resulted in increased ammonia production in isolated cortical tubules. The rates of these processes were comparable. 4. We conclude that recycling of nitrogen through glutamine synthesis and glutamine hydrolysis could play a quantitatively significant role in the control of ammonia excretion by the kidney, particularly in acute acidosis where the fall in pH seems to inhibit glutamine synthesis.

Renal Synthesis of Bile Acid Sulphates: Evidence from Man and the Isolated Perfused Rat Kidney

1976 ◽  
Vol 50 (2) ◽  
pp. 25P-26P
Author(s):  
J. A. Summerfield ◽  
J. L. Gollan ◽  
B. H. Billing
Keyword(s):  
Bile Acid ◽  
Rat Kidney ◽  
Isolated Perfused Rat Kidney ◽  
Perfused Rat Kidney

Potent vasoconstriction of the isolated perfused rat kidney by leukotrienes C4 and D4

1983 ◽  
Vol 61 (4) ◽  
pp. 325-328 ◽  
Author(s):  
A. Rosenthal ◽  
C. R. Pace-Asciak
Keyword(s):  
Guinea Pig ◽  
Rat Kidney ◽  
Guinea Pig Ileum ◽  
Rat Stomach ◽  
Isolated Kidney ◽  
Isolated Perfused Rat Kidney ◽  
Isolated Rat Kidney ◽  
Perfused Rat Kidney ◽  
Isolated Rat

Chemically synthesized leukotriene C4, D4, and E4 have been compared for their effects on the isolated Krebs-perfused rat kidney, rat stomach strip, and guinea pig ileum. C4 was more potent than D4 or E4 at all concentrations tested in contracting the rat stomach strip and in constricting the isolated rat kidney, while D4 was more potent than C4 or E4 in contracting the guinea pig ileum. While the effect of leukotrienes on the isolated kidney was blocked dose dependantly by FPL 55712, a blocker of leukotriene action, it was not blocked by the presence of either indomethacin, a cyclooxygenase blocker, or OKY-1581, a blocker of thromboxane synthesis. These results indicate that leukotriene action in the kidney is of a direct nature and is not mediated via activation of the prostaglandin pathway, especially thromboxane A2 synthesis.

The Effect of Angiotensin upon the Vasculature of the Isolated Perfused Rat Kidney

1974 ◽  
Vol 46 (5) ◽  
pp. 647-650
Author(s):  
R. B. Cross ◽  
J. W. Trace ◽  
J. R. Vattuone
Keyword(s):  
Angiotensin Ii ◽  
Perfusion Pressure ◽  
Rat Kidney ◽  
Total Flow ◽  
Renal Vasculature ◽  
Low Concentrations ◽  
Perfused Rat Kidney ◽  
Renal Flow ◽  
Intrarenal Distribution ◽  
Isolated Rat

1. The effect of angiotensin II-amide upon the intrarenal distribution of perfusate was studied in the isolated rat kidney. 2. Low concentrations of angiotensin, 4·86 pmol/l (0·005 μg/l), reduced the flow rate through the papilla but did not alter total flow. 3. Higher concentrations of angiotensin, 0·486 nmol/l (0·5 μg/l), reduced total renal flow but did not decrease papillary perfusion. 4. In these experiments the perfusion pressure was maintained constant, indicating that the changes in flow were due to a direct effect of angiotensin upon the renal vasculature.

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