Developmental Changes of Glutamate Dehydrogenase Activity in Rat Liver Mitochondria and Its Enhancement by Branched-Chain Amino Acids

Neonatology ◽  
1992 ◽  
Vol 62 (2-3) ◽  
pp. 83-88 ◽  
Author(s):  
Katsuto Eguchi ◽  
Masaru Yonezawa ◽  
Yukiteru Mitsui ◽  
Yuji Hiramatsu
Keyword(s):  
Amino Acids ◽  
Glutamate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Branched Chain Amino Acids ◽  
Developmental Changes ◽  
Rat Liver Mitochondria ◽  
Glutamate Dehydrogenase Activity ◽  
Branched Chain

scholarly journals Metabolic consequences of methylenecyclopropylglycine poisoning in rats

1991 ◽  
Vol 274 (2) ◽  
pp. 395-400 ◽  
Author(s):  
K Melde ◽  
S Jackson ◽  
K Bartlett ◽  
H S A Sherratt ◽  
S Ghisla
Keyword(s):  
Amino Acids ◽  
Ketone Bodies ◽  
Blood Glucose Concentration ◽  
Plasma Concentrations ◽  
Liver Mitochondria ◽  
Branched Chain Amino Acids ◽  
Oxidation Products ◽  
Rat Liver Mitochondria ◽  
Toxic Metabolite ◽  
Branched Chain

We describe the effects of methylenecyclopropylglycine in fasted rats. A 75% decrease in the blood glucose concentration and an increase of lactate and pyruvate were observed 6 h after administration of 100 mg of this amino acid/kg. By contrast with the effects reported for hypoglycin [Williamson & Wilson (1965) Biochem. J. 94, 19c-21c], the plasma concentrations of ketone bodies decreased after administration of methylenecyclopropylglycine and the concentrations of branched-chain amino acids in the plasma were increased 6-fold. The oxidation of decanoylcarnitine or of palmitate was nearly completely inhibited in rat liver mitochondria from methylenecyclopropylglycine-poisoned rats. The activities of acetoacetyl-CoA and of 3-oxoacyl-CoA thiolase were decreased to 25% and less than 10% of the controls. There was a pronounced aciduria, due to the excretion of dicarboxylic acids and of oxidation products of branched-chain amino acids. The accumulation of the toxic metabolite methylenecyclopropylformyl-CoA in the mitochondrial matrix was detected after administration of methylenecyclopropylglycine. Similarly we confirmed experimentally that methylenecyclopropylacetyl-CoA accumulates in mitochondria incubated with methylenecyclopropylpyruvate.

scholarly journals Developmental changes in rat liver branched-chain 2-oxo acid dehydrogenase

1982 ◽  
Vol 204 (2) ◽  
pp. 487-492 ◽  
Author(s):  
E E May ◽  
M E May ◽  
R P Aftring ◽  
M G Buse
Keyword(s):  
Amino Acids ◽  
Rat Liver ◽  
Maternal Diabetes ◽  
Perinatal Period ◽  
Branched Chain Amino Acids ◽  
Developmental Changes ◽  
Acid Dehydrogenase ◽  
Period 2 ◽  
Liver Homogenates ◽  
Branched Chain

Branched-chain 2-oxo acid dehydrogenase catalyses the first irreversible step in the degradation of the branched-chain amino acids leucine, isoleucine and valine. With specifically labelled 4-methyl-2-oxo[1-14C]pentanoate as substrate, the enzyme's activity was measured in rat liver homogenates. Activity (per g wet wL of liver or per mg of protein) increased most rapidly during the perinatal period (2 days before to 1 day after birth), reaching approximately adult values by the time of weaning. The apparent Vmax, of the enzyme increased with age, but its Km appeared unchanged. The data suggest that hepatic branched-chain 2-oxo acid dehydrogenase is induced or activated during the perinatal period. The enzyme's activity at birth was unaffected by maternal diabetes, or by treating the mother with pharmacological doses of corticosterone or 3,3',5-tri-iodothyronine, during the last 5 days of pregnancy.

Effect of carnitine on branched-chain amino acid oxidation by liver and skeletal muscle.

1978 ◽  
Vol 234 (5) ◽  
pp. E494 ◽  
Author(s):  
H S Paul ◽  
S A Adibi
Keyword(s):  
Amino Acids ◽  
Liver Mitochondria ◽  
Branched Chain Amino Acids ◽  
Diabetic Rats ◽  
Acid Oxidation ◽  
Acyltransferase Activity ◽  
Remarkable Effect ◽  
Carnitine Acyltransferase ◽  
Branched Chain Amino Acid ◽  
Branched Chain

The effect of L-carnitine (0.5-2.0 mM) on the rates of alpha-decarboxylation of 1-14C-labeled branched-chain amino acids by gastrocnemius muscle and liver homogenates of fed rats was investigated. Carnitine increased the rate of alpha-decarboxylation of leucine (125%) and valine (28%) by muscle, but it was without effect on the oxidation of these amino acids by liver. Carnitine increased the rate of alpha-decarboxylation of alpha-ketoisocaproate by both tissues. This effect was more pronounced in muscle (130% increase) than in liver (41% increase). The activity of carnitine acyltransferase, with isovaleryl-CoA as a substrate, was 18 times higher in muscle mitochondria than in liver mitochondria. Both starvation and diabetes increased the rate of alpha-decarboxylation of leucine by muscle without having a remarkable effect on the concentration of carnitine or the activity of carnitine acyltransferase. We conclude that: a) carnitine stimulates decarboxylation of branched-chain amino acids by increasing the conversion of their ketoanalogues into carnitine esters, b) a greater carnitine acyltransferase activity in muscle than in liver may be responsible for the greater carnitine effect in muscle, c) carnitine does not appear responsible for the enhancement of leucine oxidation by muscle of starved and diabetic rats.

scholarly journals Electron microscopic localization of glutamate dehydrogenase in rat liver mitochondria by an immunogold procedure and monoclonal and polyclonal antibodies.

1986 ◽  
Vol 34 (7) ◽  
pp. 913-922 ◽  
Author(s):  
E Knecht ◽  
A Martinez-Ramon ◽  
S Grisolia
Keyword(s):  
Glutamate Dehydrogenase ◽  
Rat Liver ◽  
Polyclonal Antibodies ◽  
Protein A ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
Gold Particles ◽  
Parenchymal Cells

Glutamate dehydrogenase (GDH) was localized in rat liver by indirect electron microscopic immunogold, using different sizes of gold particles and monoclonal and polyclonal antibodies. Using the protein A-gold technique in double immunocytochemical experiments, both antibodies, at their optimal dilutions, gave similar results. A novel assessment of the distribution of GDH was made by measurements of the number of gold particles per square micrometer of cross-sectional images of individual mitochondria. The data indicate intracellular homogeneity among mitochondria in individual parenchymal cells. The enzyme is almost absent in non-parenchymal cells. Finally, GDH was found mainly in association with the mitochondrial inner membrane.

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