scholarly journals N-Acetylglutamate in rat liver during foetal development

1984 ◽  
Vol 222 (3) ◽  
pp. 837-838 ◽  
Author(s):  
M Van Dijk ◽  
P Lund
Keyword(s):  
Rat Liver ◽  
Urea Cycle ◽  
Developmental Pattern ◽  
Foetal Development ◽  
Tissue Content ◽  
Foetal Rat ◽  
Foetal Life

N-Acetylglutamate is present in foetal rat liver at 17 days' gestation. The tissue content (approx. 50 nmol/g wet wt.) remains constant during later foetal life. The appearance of N-acetylglutamate does not parallel the developmental pattern of the urea cycle.

Differentiation of liver peroxisomes in the foetal and newborn rat. Cytochemistry of catalase and D-aminoacid oxidase

Development ◽  
1985 ◽  
Vol 88 (1) ◽  
pp. 151-163
Author(s):  
S. Stefanini ◽  
M. G. Farrace ◽  
M. P. Cerù Argento
Keyword(s):  
Rat Liver ◽  
Gradual Increase ◽  
Individual Cell ◽  
Newborn Rats ◽  
Newborn Rat ◽  
Foetal Development ◽  
Tissue Area ◽  
Foetal Rat ◽  
Parenchymal Cells ◽  
Liver Peroxisomes

Organules containing cytochemically detectable amounts of catalase and D-aminoacid oxidase activities are observed between the 14th and 21st day of development in the parenchymal cells of the foetal rat liver and in the liver of newborn rats. As early as 14 to 15 days, a limited number of small microperoxisomes, scattered in the cytoplasm of very few hepatocytes, can be found. These are roundish shaped, have a granulous matrix and contain very low, hardly detectable levels of the above mentioned enzymes. In later development both the size and the enzymatic content of the organules gradually increase, approaching adult levels at the end of foetal development. Starting from the 18th to 19th day of intrauterine life nucleoids can be seen in many peroxisomes. The morphological and biochemical maturation from microperoxisomes to peroxisomes is accompanied by a gradual increase in the number of stainable organules, both per individual cell and per tissue area.

scholarly journals Changes in the activities of the enzymes of urea synthesis caused by dexamethasone and dibutyryladenosine 3′:5′-cyclic monophosphate in foetal rat liver maintained in organ culture

1976 ◽  
Vol 160 (2) ◽  
pp. 159-162 ◽  
Author(s):  
E Edkins ◽  
N C R Rïhä
Keyword(s):  
Cyclic Amp ◽  
Organ Culture ◽  
Rat Liver ◽  
Urea Cycle ◽  
Defined Medium ◽  
Urea Synthesis ◽  
Dibutyryl Cyclic Amp ◽  
Carbamoyl Phosphate ◽  
Foetal Rat ◽  
Ornithine Transcarbamoylase

Liver explants from 19-day foetal rats were maintained in organ culture, in a defined medium, for up to 48h. Both 6-N,2′-O-dibutyryl cyclic AMP, in the presence of theophylline, and dexamethasone caused an increase in the activities of carbamoyl phosphate synthase, argininosuccinate synthetase, argininosuccinate lyase and arginase. These increases could be abolished by simultaneously incubating the explants with cycloheximide. No change in the activity of ornithine transcarbamoylase was found with either hormone. Previous work has shown that injection of corticosteroids into 19.5-day foetal rats in utero did not cause an increase in the arginine synthetase system. Present results suggest that this lack of effect is not due to any incompetence of the foetal rat liver at this stage to respond to this agent. The observations on ornithine transcarbamoylase activity suggest that this enzyme is induced in the liver of the perinatal rat by neither corticosteroids nor hormones acting via cyclic AMP, and it may be that all the enzymes of the urea cycle are induced physiologically by an agent or agents as yet unidentified.

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.

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.

A Pre-Modern Description of Emergence: Albertus Magnus on Human Foetal Development

KronoScope ◽  
2012 ◽  
Vol 12 (2) ◽  
pp. 245-256
Author(s):  
Dennis Costa
Keyword(s):  
Thirteenth Century ◽  
First Century ◽  
Philosophical Psychology ◽  
Foetal Development ◽  
Emergent Systems ◽  
Foetal Life ◽  
Human Psyche ◽  
Twenty First Century

AbstractBoth the theory and the terminology of Albertus Magnus’s philosophical psychology in the thirteenth century bear an extraordinary resemblance to twenty-first century descriptions of emergent systems. In Albert’s description of the temporal drama of human foetal life, the emergent, ‘intellectual’ energies of humanpsychêoranimaor soul cannot be at all predicated on the material or psychic agents that give rise to them. Though standing in a real continuity with those natural, causal agents, human psyche knows itself as existing discontinuously from them and as enacting, in and through the dimension of time, kinds of knowledge and types of experience which display complex potentialities that appear to be irreducible, or, at the least, not fully measurable: in art, in science, and also in cultic action.

Modulation of mRNA Levels for Urea Cycle Enzymes in Rat Liver by Diet and Hormones

1986 ◽  
Vol 478 (1 Metabolic Reg) ◽  
pp. 292-294 ◽  
Author(s):  
SIDNEY M. MORRIS ◽  
CAROLE L. MONCMAN ◽  
WILLIAM E. O'BRIEN
Keyword(s):  
Rat Liver ◽  
Urea Cycle ◽  
Mrna Levels ◽  
Urea Cycle Enzymes

Effect of Adrenalectomy on the Activity of Enyzmes of the Urea Cycle in Rat Liver

Nature ◽  
1961 ◽  
Vol 191 (4795) ◽  
pp. 1302-1303 ◽  
Author(s):  
PATRICIA McLEAN
Keyword(s):  
Rat Liver ◽  
Urea Cycle
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