scholarly journals Effect of azo-dye carcinogenesis on enzymes concerned with urea synthesis in rat liver

1964 ◽  
Vol 91 (3) ◽  
pp. 464-473 ◽  
Author(s):  
P McLean ◽  
E Reid ◽  
MW Gurney
Keyword(s):  
Rat Liver ◽  
Azo Dye ◽  
Urea Synthesis

scholarly journals Real-time study of the urea cycle using 15N n.m.r. in the isolated perfused rat liver

1992 ◽  
Vol 287 (3) ◽  
pp. 813-820 ◽  
Author(s):  
A Geissler ◽  
K Kanamori ◽  
B D Ross
Keyword(s):  
Rat Liver ◽  
Urea Cycle ◽  
Isolated Perfused Rat Liver ◽  
15N Recovery ◽  
Urea Synthesis ◽  
Perfused Liver ◽  
Biochemical Assays ◽  
Low Concentrations ◽  
15N Urea ◽  
Rate Limiting

1. Isolated rat liver was perfused with 10 mM-15NH4Cl, 5 mM-lactate and 1 mM-ornithine, or with 3 mM-[15N]alanine and 1 mM-ornithine, in haemoglobin-free medium. The liver was physiologically stable for over 3 h and synthesized urea at the rate of 1.15 mumol.min-1.g of liver-1 (15NH4(+)-perfused) or 0.41 mumol.min-1.g-1 ([15N]alanine-perfused). 2. The perfused liver was continuously monitored by 15N n.m.r. spectroscopy at 20.27 MHz for 15N. Well-resolved 15N resonances of precursors and intermediates of the urea cycle, present at tissue concentrations of 0.2-3.0 mumol/g, were observed from the intact liver in 5-40 min of acquisition. Key metabolites in liver extract and the final perfusion medium were analysed by n.m.r. and by biochemical assays to determine fractional 15N enrichment and the total 15N recovery. 3. In 15NH4(+)-perfused liver (n = 6), 15N incorporation into glutamate and alanine (1.0-1.3 mumol/g), as well as progressive formation of [15N2]urea, was observed during the first 2 h of perfusion. In the second and third hour, hepatic concentrations of [omega-15N]citrulline and [omega, omega'-15N]argininosuccinate increased to n.m.r.-detectable levels (0.3-0.9 mumol/g). The [15N]aspartate pool was large in the absence of added ornithine, but on its addition was rapidly incorporated into argininosuccinate (n = 3). 4. In [15N]alanine-perfused liver, major metabolites were [15N]glutamate, [gamma-15N]glutamine and [15N]urea. Urea-cycle intermediates were undetectable. 5. The results suggest that, in intact liver provided with excess ammonia, low concentrations of cytosolic argininosuccinate synthetase and argininosuccinate lyase limited the rate of metabolite flux in the urea cycle. By contrast, in alanine-perfused liver at a physiological rate of urea synthesis, mitochondrial carbamoylphosphate synthetase was rate-limiting. 6. The potential utility of 15N n.m.r. for study of metabolite channelling through urea-cycle enzymes in intact liver is discussed.

Analysis of Regulatory Factors for Urea Synthesis by Isolated Perfused Rat Liver

1975 ◽  
Vol 77 (3) ◽  
pp. 671-678 ◽  
Author(s):  
Takeyori SAHEKI ◽  
Michio TSUDA ◽  
Tomi TANAKA ◽  
Nobuhiko KATUNUMA
Keyword(s):  
Rat Liver ◽  
Isolated Perfused Rat Liver ◽  
Urea Synthesis ◽  
Perfused Rat Liver ◽  
Regulatory Factors

Regulation of Urea Synthesis in Rat Liver

1978 ◽  
Vol 84 (6) ◽  
pp. 1423-1430 ◽  
Author(s):  
Takeyori SAHEKI ◽  
Tomoichi OHKUBO ◽  
Tsunehiko KATSUNUMA
Keyword(s):  
Rat Liver ◽  
Urea Synthesis

Changes of aldolase A and B messenger RNA levels in rat liver during azo-dye-induced hepatocarcinogenesis

1984 ◽  
Vol 124 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Makoto Daimon ◽  
Ken-ichi Tsutsumi ◽  
Jun-ichi Sato ◽  
Reiko Tsutsumi ◽  
Kiichi Ishikawa
Keyword(s):  
Rat Liver ◽  
Messenger Rna ◽  
Azo Dye ◽  
Aldolase A ◽  
Rna Levels

scholarly journals The effects of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) on glycolysis and biosynthetic processes of the isolated perfused rat liver

1972 ◽  
Vol 128 (3) ◽  
pp. 711-720 ◽  
Author(s):  
J. F. Biebuyck ◽  
Patricia Lund ◽  
H. A. Krebs
Keyword(s):  
Rat Liver ◽  
Lactate Production ◽  
Fold Increase ◽  
Isolated Perfused Rat Liver ◽  
Urea Synthesis ◽  
Perfused Rat Liver ◽  
Anaesthetic Agents ◽  
Metabolic Functions ◽  
Tissue Content ◽  
Gluconeogenesis From Alanine

1. With reference to the post-operative dysfunction of the liver observed after halothane anaesthesia, the effects of the anaesthetic on some metabolic functions were studied in the isolated perfused rat liver. Oxygen uptake, glycolysis, gluconeogenesis and urea synthesis were affected by halothane at a concentration (2.5% of the gas phase) within the range used in clinical anaesthesia. 2. At this concentration of halothane uptake of oxygen was inhibited in livers from both fed and starved rats. 3. In livers from fed rats there was a 16-fold increase in lactate production. This was accompanied by a fivefold decrease in the tissue content of 2-oxoglutarate and a more than twofold decrease in citrate. The calculated [free NAD+]/[free NADH] ratio in both cytoplasm and mitochondria was lower in the halothane-exposed livers than in controls. 4. In livers of starved rats the rate of gluconeogenesis from lactate was decreased by halothane to 30% of the control rate. 5. Halothane inhibited gluconeogenesis from alanine and propionate to the same extent as from lactate, whereas glucose formation from dihydroxyacetone, glycerol, fructose and sorbitol was relatively unaffected. 6. During gluconeogenesis from 10mm-lactate the tissue content of ATP was decreased by 50%, glutamate by 50% and 2-oxoglutarate was decreased eightfold in the halothane-exposed livers. 7. Halothane decreased urea synthesis in the presence of 10mm-NH4Cl and 2mm-ornithine to 15% of the control rate. 8. The inhibitions of gluconeogenesis and urea synthesis were completely abolished within 15min of withdrawal of the anaesthetic. 9. The stimulation of uptake of oxygen brought about by the addition of lactate or precursors of urea was abolished by halothane. 10. Effects on gluconeogenesis similar to those of halothane occurred in livers exposed to the anaesthetic methoxyflurane, although normal rates were not restored on withdrawal of the drug. Other anaesthetic agents tested (ketamine–HCl and trichloroethylene) decreased gluconeogenesis to 66% of the control rate. 11. The inhibitory effects of halothane are consistent with an interference at the stage of the NADH dehydrogenase of the electron-transport chain.

Sign in / Sign up

Export Citation Format

Share Document