scholarly journals Prenatal and postnatal changes in the content and species of ferritin in rat liver

1972 ◽  
Vol 129 (2) ◽  
pp. 455-462 ◽  
Author(s):  
Maria C. Linder ◽  
Joan R. Moor ◽  
Laura E. Scott ◽  
Hamish N. Munro
Keyword(s):  
Litter Size ◽  
Rat Liver ◽  
Intraperitoneal Injection ◽  
Total Iron ◽  
Adult Liver ◽  
Stage Of Development ◽  
Low Concentrations ◽  
Adult Kidney ◽  
Ferritin Iron ◽  
Liver Ferritin

The iron and ferritin content of rat liver and the species of ferritin present were examined from 4 days before to 3 weeks after birth. 1. Total iron and ferritin iron accumulated rapidly during the last days of gestation and from the second postnatal day underwent a steady depletion. 2. The amount of iron deposited before birth in the liver of each pup varied inversely with litter size and could be increased moderately by injection of iron into the mother before mating. 3. Intraperitoneal injection of iron 1 day after birth doubled the concentration of total iron, ferritin iron and ferritin protein in the liver over the next 24h, but at 3 weeks after birth it raised the very low concentrations of iron and ferritin severalfold. 4. As shown by electrophoretic migration, ferritin and dissociated ferritin subunits prepared from the livers of rats from 4 days before to 3 weeks after birth differed from those of adult liver ferritin and were indistinguishable from those of adult kidney and spleen ferritin. Treatment with iron at 3 weeks of age induced formation of a ferritin with electrophoretic properties resembling those of adult liver. It is concluded that iron given at this stage of development may activate the genetic cistron for adult liver ferritin.

scholarly journals Aldehyde dehydrogenase in 2-acetaminofluorene-induced rat hepatomas. Ontogeny and evidence that the new isoenzymes are not due to normal gene de-repression

1977 ◽  
Vol 164 (1) ◽  
pp. 119-123 ◽  
Author(s):  
Ronald Lindahl
Keyword(s):  
Rat Liver ◽  
Aldehyde Dehydrogenase ◽  
Double Diffusion ◽  
Normal Liver ◽  
Normal Adult ◽  
Sprague Dawley ◽  
Adult Liver ◽  
Aldehyde Dehydrogenases ◽  
Adult Rat ◽  
Liver Aldehyde Dehydrogenase

The pre- and post-natal ontogeny of Sprague–Dawley rat liver aldehyde dehydrogenase [aldehyde–NAD(P)+ oxidoreductase, EC 1.2.1.5] is described. At no time in its ontogenetic development does normal liver aldehyde dehydrogenase exhibit any of the characteristics of a series of unique aldehyde dehydrogenases that can be isolated from 2-acetamidofluorene-induced rat hepatomas. Enzyme activity is first detectable in 15-day foetal liver and gradually increases throughout pre- and post-natal development until adult activities are attained by day 49 after birth. Electrophoretically, normal aldehyde dehydrogenase, throughout its ontogeny, exists as the same single isoenzyme found in normal adult liver. Isoelectric points for two normal liver isoenzymes demonstrable by isoelectric focusing are pH5.9 and 6.0. The immunochemical properties of aldehyde dehydrogenase during its ontogeny are identical with those of normal adult liver aldehyde dehydrogenase when tested against anti-(hepatoma aldehyde dehydrogenase) serum in Ouchterlony double-diffusion tests. The results indicate that the hepatoma-specific aldehyde dehydrogenases are not the result of the de-repression of genes normally repressed in adult rat liver or in some other adult tissue.

scholarly journals The roles of phospholipase D and a GTP-binding protein in guanosine 5′-[γ-thio]triphosphate-stimulated hydrolysis of phosphatidylcholine in rat liver plasma membranes

1990 ◽  
Vol 272 (3) ◽  
pp. 749-753 ◽  
Author(s):  
K M Hurst ◽  
B P Hughes ◽  
G J Barritt
Keyword(s):  
Rat Liver ◽  
Phospholipase D ◽  
Plasma Membranes ◽  
Regulatory Protein ◽  
Gtp Binding ◽  
Liver Plasma Membranes ◽  
Low Concentrations ◽  
Rat Liver Plasma Membranes ◽  
Triton X ◽  
Hydrolysis Of

1. Guanosine 5′-[gamma-thio]triphosphate (GTP[S]) stimulated by 50% the rate of release of [3H]choline and [3H]phosphorylcholine in rat liver plasma membranes labelled with [3H]choline. About 70% of the radioactivity released in the presence of GTP[S] was [3H]choline and 30% was [3H]phosphorylcholine. 2. The hydrolysis of phosphorylcholine to choline and the conversion of choline to phosphorylcholine did not contribute to the formation of [3H]choline and [3H]phosphorylcholine respectively. 3. The release of [3H]choline from membranes was inhibited by low concentrations of SDS or Triton X-100. Considerably higher concentrations of the detergents were required to inhibit the release of [3H]phosphorylcholine. 4. Guanosine 5′-[beta gamma-imido]triphosphate and guanosine 5′-[alpha beta-methylene]triphosphate, but not adenosine 5′-[gamma-thio]-triphosphate, stimulated [3H]choline release to the same extent as did GTP[S]. The GTP[S]-stimulated [3H]choline release was inhibited by guanosine 5′-[beta-thio]diphosphate, GDP and GTP but not by GMP. 5. It is concluded that, in rat liver plasma membranes, (a) GTP[S]-stimulated hydrolysis of phosphatidylcholine is catalysed predominantly by phospholipase D with some contribution from phospholipase C, and (b) the stimulation of phosphatidylcholine hydrolysis by GTP[s] occurs via a GTP-binding regulatory protein.

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 Influence of mitochondria on phospholipid synthesis in preparations from rat liver

1973 ◽  
Vol 136 (3) ◽  
pp. 467-475 ◽  
Author(s):  
J. B. Roberts ◽  
F. L. Bygrave
Keyword(s):  
Rat Liver ◽  
Inhibitory Effect ◽  
Total Radioactivity ◽  
Phospholipid Synthesis ◽  
Low Concentrations ◽  
Absolute Requirement ◽  
Reconstituted System ◽  
Protein Incorporation ◽  
Very High ◽  
Cellular Phospholipid

1. The addition of mitochondria to an incubation system containing the soluble and microsomal fractions of rat liver enhances severalfold the incorporation of each of ethanolamine, phosphorylethanolamine and CDP-ethanolamine into phosphatidylethanolamine. 2. In the presence of microsomal, mitochondrial and soluble fractions, CDP-ethanolamine exhibits the greatest initial rate of incorporation (approx. 6nmol/h per mg of protein), being slightly faster than that of phosphorylethanolamine (approx. 5nmol/h per mg of protein). Incorporation of ethanolamine proceeds very slowly for the first 20min and only after 30min gives rates approaching those of the other two precursors. 3. By using a substrate ‘dilution’ technique it was shown that in the reconstituted system the affinity of each of the enzymes for their respective substrates is very high: 10μm for ethanolamine, 25μm for phosphorylethanolamine and 5μm for CDP-ethanolamine. 4. Isolation of the mitochondrial and microsomal fractions from the medium after incubation together with phosphorylethanolamine showed that about 70% of the total radioactivity was present in the microsomal fraction and about 30% in the mitochondria after only 20min. Similar experiments with ethanolamine as precursor revealed that after 20min only about 15% of the total radioactivity was present in the mitochondria but that after 40min about 30% was present in this fraction. 5. Heating and phospholipase treatment of mitochondria, but not freeze-thawing, eliminated the stimulatory effect of mitochondria on phospholipid synthesis. 6. The reconstituted system exhibits an absolute requirement for Mg2+(2mm gave maximal rates) and is inhibited by very low concentrations of Ca2+(100μm-Ca2+produced half-maximal inhibition with 3mm-Mg2+). Further addition of Mg2+overcame the Ca2+inhibition, suggesting that the inhibitory effect is readily reversible. 7. The concept that modification of the Mg2+/Ca2+ratio is a means of controlling the rate of cellular phospholipid synthesis is introduced.

scholarly journals The effects of glucagon and insulin on adenosine 3′:5′-cyclic monophosphate concentrations in an organ culture of mature rat liver

1973 ◽  
Vol 132 (4) ◽  
pp. 765-773 ◽  
Author(s):  
Kenneth Siddle ◽  
Barbara Kane-Maguire ◽  
Anthony K. Campbell
Keyword(s):  
Cyclic Amp ◽  
Organ Culture ◽  
Rat Liver ◽  
Incubation Medium ◽  
Radioactive Tracer ◽  
Maximal Increase ◽  
Low Concentrations ◽  
Glucagon And Insulin ◽  
Millipore Filters ◽  
Glucagon Concentration

1. A modified radioimmunoassay for cyclic AMP was developed from the method of Steiner et al. (1969). Cyclic [3H]AMP was used as the radioactive tracer. Free and antibody-bound nucleotides were separated by adsorption of protein to Millipore filters. The assay was used to measure amounts of cyclic AMP down to 0.1pmol in 50μl. 2. The effect of glucagon on cyclic AMP content in pieces of mature rat liver maintained for 6 days in organ culture was studied. 3. Cyclic AMP content in the tissue reached a maximum in 5–15min and then decreased. This may have been partly due to an inhibitor of glucagon action formed in the tissue. Small amounts of cyclic AMP were released into the incubation medium. 4. The maximal increase in cyclic AMP content produced by glucagon decreased over 6 days in culture. However, liver pieces cultured for 2 and 6 days were more sensitive to low concentrations of glucagon than were fresh liver pieces. Glucagon concentrations for half-maximal effects were approx. 1μm and 0.05μm for fresh liver and 2-day cultured liver respectively. 5. Insulin (3.5μm) lowered the cyclic AMP content by 30% in the presence of a submaximal glucagon concentration in liver cultured for 2 days. No effect of insulin was demonstrated on fresh liver pieces. 6. Insulin and glucagon were rapidly destroyed by fresh liver pieces.

scholarly journals Proton translocation by the mitochondrial cytochrome b-c1 complex is inhibited by NN′-dicyclohexylcarbodi-imide

1982 ◽  
Vol 206 (2) ◽  
pp. 419-421 ◽  
Author(s):  
B D Price ◽  
M D Brand
Keyword(s):  
Electron Transport ◽  
Cytochrome Oxidase ◽  
Cytochrome B ◽  
Rat Liver ◽  
Proton Translocation ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Cytochrome ◽  
Low Concentrations ◽  
Mitochondrial Cytochrome B

NN'-Dicyclohexylcarbodi-imide at low concentrations decreases the H+/2e ratio for rat liver mitochondria over the span succinate to oxygen from 5.9 +/- 0.3 (mean +/- S.E.M.) to 4.0 +/- 0.1 and for the cytochrome b-c1 complex from 3.8 +/- 0.2 to 1.9 +/- 0.1, but has little effect on the H+/2e ratio of cytochrome oxidase. The decrease in stoicheiometry is due, not to uncoupling or inhibition of electron transport, but to inhibition of proton translocation. NN'-Dicyclohexylcarbodi-imide thus ‘decouples’ proton translocation in the cytochrome b-c1 complex.

The Isoferritin Composition of Rat Liver During Bleeding Induced Catabolism of Liver Ferritin

1984 ◽  
pp. 199-202
Author(s):  
F.M.J. ZUYDERHOUDT ◽  
P.L.M. VIJVERBERG ◽  
W.O. SCHREUDER ◽  
C. LINTHORST ◽  
G.G.A. JÖRNING
Keyword(s):  
Rat Liver ◽  
Liver Ferritin

Regulation of oxygen consumption in rat liver slices

1964 ◽  
Vol 206 (5) ◽  
pp. 1091-1094 ◽  
Author(s):  
Herbert L. Kayne ◽  
Natsu Taylor ◽  
Norman R. Alpert
Keyword(s):  
Oxygen Consumption ◽  
Rat Liver ◽  
Adenine Nucleotides ◽  
Pyridine Nucleotide ◽  
Liver Slices ◽  
Low Concentrations ◽  
The Relationship ◽  
Fasted Rats

Oxygen consumption, ATP, ADP, and reduced and oxidized pyridine nucleotide were measured in liver slices which were taken from fed, fasted, and refed rats and subjected to varying durations of anoxia. Oxygen consumption was low in slices from fasted rats and was increased after anoxia in all three groups of rats. Liver slices from fasted rats were also characterized by low concentrations of adenine nucleotides and oxidized pyridine nucleotide. These decreased during anoxia in all groups. Reduced pyridine nucleotide was low in fasted rats, intermediate in fed, and high in refed rats. There was an increase in concentration after 5 min of anoxia. The relationship among these variables is discussed in regard to the concept of nucleotide control of oxygen consumption.

Sign in / Sign up

Export Citation Format

Share Document