scholarly journals Changes in activity of some enzymes involved in glucose utilization and formation in developing rat liver

1968 ◽  
Vol 106 (2) ◽  
pp. 321-329 ◽  
Author(s):  
R. G. Vernon ◽  
D G Walker
Keyword(s):  
Malate Dehydrogenase ◽  
Rat Liver ◽  
Postnatal Period ◽  
Supernatant Fraction ◽  
Atp Citrate Lyase ◽  
Carboxylase Activity ◽  
Phosphogluconate Dehydrogenase ◽  
Citrate Lyase ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Developing Rat

1. The activities of some enzymes involved in both the utilization of glucose (pyruvate kinase, ATP citrate lyase, NADP-specific malate dehydrogenase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and NADP-specific isocitrate dehydrogenase, all present in the supernatant fraction of liver homogenates) and the formation of glucose by gluconeogenesis (glucose 6-phosphatase in the whole homogenate and fructose 1,6-diphosphatase, phosphopyruvate carboxylase, NAD-specific malate dehydrogenase and fumarase in the supernatant fraction) have been determined in rat liver around birth and in the postnatal period until the end of weaning. 2. The activities of those enzymes involved in the conversion of glucose into lipid are low during the neonatal period and increase with weaning. NADP-specific malate dehydrogenase first appears and develops at the beginning of the weaning period. 3. The marked increase in cytoplasmic phosphopyruvate carboxylase activity at birth is probably the major factor initiating gluconeogenesis at that time. 4. The results are discussed against the known changes in dietary supplies and the known metabolic patterns during the period of development.

The effects of pregnancy, lactation and involution on the metabolism of glucose and acetate by rat liver tissue

1973 ◽  
Vol 40 (3) ◽  
pp. 339-351 ◽  
Author(s):  
R. W. Smith
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Milk Fat ◽  
Late Pregnancy ◽  
Acetyl Coa Carboxylase ◽  
Atp Citrate Lyase ◽  
Phosphogluconate Dehydrogenase ◽  
Citrate Lyase ◽  
Pregnancy And Lactation ◽  
Glucose 6 Phosphate Dehydrogenase

SummaryThe incorporation of 14C from [1-14C] and [6-14C]glucose and [2-14C]acetate into CO2 and fatty acids by rat liver slices was measured at intervals during pregnancy, lactation and involution.During late pregnancy, the rates of oxidation of the C-1 and C-6 atoms of glucose were respectively 65 and 40 % higher than those for unmated animals. These increases were maintained during lactation, but the highest values were observed 3 days after weaning. Pregnancy and lactation had little effect on the oxidation of [2-14C]acetate.The incorporation of14C from all 3 labelled substrates into fatty acids was increased by a factor of 3–4 during late pregnancy. There were further increases during lactation, and 3 days after weaning the values were as much as 10 times as high as those for unmated animals.The incorporation of both [14C]glucose and [14C]acetate into cholesterol was increased by a factor of 6–7 during lactation.The activities of the enzymes glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, ATP citrate lyase and acetyl-CoA carboxylase were also increased during lactation and involution.The similarity between the changes summarized above and those brought about by changes in the pattern of food intake is discussed, and the idea that fatty acids synthesized from non-lipid precursors in the liver may make some contribution to the formation of milk fat is also considered.

Enzyme Activities of NADPH-Forming Metabolic Pathways in Normal and Leukemic Leukocytes

1975 ◽  
Vol 21 (7) ◽  
pp. 880-883 ◽  
Author(s):  
Francesco Belfiore ◽  
Vito Borzi ◽  
Luigi Lo Vecchio ◽  
Elena Napoli ◽  
Agata M Rabuazzo
Keyword(s):  
Malate Dehydrogenase ◽  
Metabolic Pathways ◽  
Normal Subjects ◽  
Atp Citrate Lyase ◽  
Phosphogluconate Dehydrogenase ◽  
Myelocytic Leukemia ◽  
Citrate Lyase ◽  
Enzymatic Characteristic ◽  
I Cells ◽  
Low Activity

Abstract With respect to the enzymes of NADPH-forming metabolic pathways in human leukocytes: (a) Glucose-6phosphate dehydrogenase and phosphogluconate dehydrogenase (decarboxylating) were less active in leukocytes (mostly myeloblasts) from eight patients with acute myeloblastic leukemia (I) than in leukocytes (mostly granulocytes) from 16 normal subjects (II) or 16 patients with chronic myelocytic leukemia (III). (b) Of the enzymes of the citrate cleavage pathway, ATP citrate lyase and malate dehydrogenase (decarboxylating) (NADP+) were virtually absent in the cells studied. (c) Isocitrate dehydrogenase (NADP+), aspartate aminotransferase, and alanine aminotransferase, which, together with the much more active malate dehydrogenase, constitute a newly proposed NADPH-forming metabolic cycle, showed a higher activity in I than in II or III, and therefore could compensate, as concerns NADPHgeneration, for the low activity of pentose cycle dehydrogenases. We are not sure whether the enzymatic characteristic of I cells is attributable to their immaturity or to their leukemic nature.

Response of lipogenic enzymes to overfeeding in liver and adipose tissue of light and heavy breeds of chicks

1978 ◽  
Vol 39 (1) ◽  
pp. 151-157 ◽  
Author(s):  
Niva Shapira ◽  
I. Nir ◽  
P. Budowski
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid Synthetase ◽  
Fat Content ◽  
Acetyl Coa Carboxylase ◽  
Lipogenic Enzymes ◽  
Atp Citrate Lyase ◽  
Phosphogluconate Dehydrogenase ◽  
Citrate Lyase ◽  
Generating Capacity ◽  
Glucose 6 Phosphate Dehydrogenase

1. Chicks, 3-d-old, of a heavy breed (HB) and a light breed (LB) were overfed for 18 d. The activities of acetyl-CoA carboxylase (EC 6.4.1.2; CBX), fatty acid synthetase (FAS), ATP citrate lyase (EC 4.1.3.8; CCE), NADP-malate dehydrogenase (decarboxylating) (EC 1.1.1.40; ME), 6-glucose-6-phosphate dehydrogenase (EC 1.1.1.49; G6PDH) and phosphogluconate dehydrogenase (EC 1.1.1.44; 6PGDH) were determined in abdominal adipose tissue (AT) and liver samples of overfed and ad lib.-fed chicks. Size and fat content of liver and adipose tissue were also determined in order to evaluate the extent of obesity.2. On ad lib.-feeding HB chicks consumed more food, gained more weight and deposited more fat than the corresponding LB chicks. Their lipogenic enzymes were more active than in the LB chicks in both adipose tissue and liver. The increase in food consumption (%) that could be achieved by overfeeding was three times greater in the LB chicks than in the HB chicks.3. Overfeeding increased the weight and fat content of liver and AT in both breeds. The specific activities of CBX, FAS, CCE and ME in liver and AT increased in the LB chicks only and the total activities of liver and AT enzymes increased much more in the LB chicks than in the HB chicks in which the increase was derived mainly from tissue enlargement.4. The activity of the pentose cycle dehydrogenases was very low in liver, but in AT about one third of the NADPH generating capacity could be accounted for by these dehydrogenases.5. The results show that lipogenic enzymes of chicks respond to an increased substrate flux. It is suggested that the enlarged liver, the higher participation of AT in lipogenesis and the uninterrupted supply of cropstored excess food enable the chick to accommodate the increased amounts of substrate with only moderate enzymic adaptation.

scholarly journals The metabolic fate of the products of citrate cleavage. Adenosine triphosphate citrate lyase and nicotinamide–adenine dinucleotide phosphate-linked malate dehydrogenase in foetal and adult liver from ruminants and non-ruminants

1968 ◽  
Vol 108 (5) ◽  
pp. 705-713 ◽  
Author(s):  
R. W. Hanson ◽  
F. J. Ballard
Keyword(s):  
Fatty Acids ◽  
Malate Dehydrogenase ◽  
Rat Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Atp Citrate Lyase ◽  
Adult Rat ◽  
Liver Slices ◽  
Citrate Lyase ◽  
Foetal Rat

1. Foetal rat liver slices incorporate the C-3 of aspartate and C-2 of glutamate into fatty acids at rates equal to those observed with adult rat liver slices. Incorporation of either of these labelled carbon atoms into fatty acids would require a functioning citrate-cleavage pathway which consists of the enzymes ATP–citrate lyase, NAD–malate dehydrogenase and NADP–malate dehydrogenase. However, NADP–malate dehydrogenase is present in foetal rat liver at only 5% of the activity detectable in adult rat liver. 2. From these findings and the effect of cofactors on the formation of 14CO2 from [1,5−14C2]citrate in liver supernatant fractions (100000g), it is suggested that NADP–malate dehydrogenase limits the citrate-cleavage sequence. 3. Measurement of the citrate-cleavage pathway by incorporation studies with [3−14C]aspartate and [U−14C]glucose and by determining the activities of ATP–citrate lyase and NADP–malate dehydrogenase have shown that this sequence of reactions is present in the liver of the bovine foetus but not in the adult. However, C-2 of glutamate is not incorporated into fatty acids or non-saponifiable lipid by bovine liver slices. This finding as well as those presented above for the adult and foetal rat liver are interpreted on the basis of a competition between phosphoenolpyruvate carboxykinase and NAD–malate dehydrogenase for oxaloacetate produced by the cleavage of citrate in the cytosol.

The role of ATP citrate lyase in the transfer of acetyl groups in rat liver

1968 ◽  
Vol 158 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Yasushi Daikuhara ◽  
Takuo Tsunemi ◽  
Yoshiro Takeda
Keyword(s):  
Rat Liver ◽  
Atp Citrate Lyase ◽  
Citrate Lyase

Studies on ATP Citrate Lyase of Rat Liver

1966 ◽  
Vol 60 (5) ◽  
pp. 543-553 ◽  
Author(s):  
HIDEO INOUE ◽  
FUJIO SUZÚKI ◽  
KEIHACHI FUKUNISHI ◽  
KOZABURO ADACHI ◽  
YOSHIRO TAKEDA
Keyword(s):  
Rat Liver ◽  
Atp Citrate Lyase ◽  
Citrate Lyase

Binding of Specific ATP Citrate Lyase and Fatty Acid Synthetase Antibodies to Heavy Populations of Rat Liver Polysomes

1979 ◽  
Vol 99 (1) ◽  
pp. 209-216 ◽  
Author(s):  
Mary B. FINKELSTEIN ◽  
Michael P. AURINGER ◽  
Laura A. HALPER ◽  
Tracy C. LINN ◽  
Manoranjan SINGH ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
Fatty Acid Synthetase ◽  
Atp Citrate Lyase ◽  
Citrate Lyase

A two-step purification of ATP-citrate lyase from rat liver and its use in a fluorometric assay for N-acetylglutamate synthetase

1985 ◽  
Vol 144 (2) ◽  
pp. 604-609 ◽  
Author(s):  
Christopher Wraight ◽  
Adrienne Day ◽  
Nicholas Hoogenraad ◽  
Robert Scopes
Keyword(s):  
Rat Liver ◽  
Fluorometric Assay ◽  
Atp Citrate Lyase ◽  
Citrate Lyase

TPNH GENERATION IN THE HUMAN OVARY

1965 ◽  
Vol 49 (1) ◽  
pp. 58-64 ◽  
Author(s):  
M. H. Nielson ◽  
J. C. Warren
Keyword(s):  
Life Cycle ◽  
Corpus Luteum ◽  
Malate Dehydrogenase ◽  
Isocitrate Dehydrogenase ◽  
Relative Activity ◽  
Human Ovary ◽  
Phosphogluconate Dehydrogenase ◽  
Glucose 6 Phosphate Dehydrogenase

ABSTRACT The endogenous activities of four major supernatant enzymes which produce TPNH (glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, malate dehydrogenase and isocitrate dehydrogenase) were quantitated in both normal and pathologic human ovarian tissues. The atrophic ovary demonstrated the lowest relative activity of the pentose shunt dehydrogenases, whereas luteinized tissues displayed the highest. During the course of its life cycle, the corpus luteum of the nonpregnant female displayed a progressive rise in isocitrate dehydrogenase and a concomitant fall in glucose-6-phosphate dehydrogenase activities. The corpus luteum of pregnancy, studied at term, demonstrated the highest levels of activity of all the four enzymes quantitated.

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