Changes in lipid synthesis in rat liver during development

1. Lipogenesis, as measured by the incorporation of (14)C-labelled glucose or acetate into fatty acids in liver slices, is high in foetal and adult rat liver but is low in the liver of the suckling rat, especially with glucose as substrate. 2. The rate of synthesis of non-saponifiable lipids from glucose is about 15 times as great in the liver of the 18-day foetus as in adult liver. Activity in the newborn is negligible. 3. Glucose incorporation into fat is strongly concentration-dependent in liver slices from the adult and 2-week-old rat, but less markedly so in liver slices from the foetus. 4. Changes in the activity of hepatic citrate-cleavage enzyme (ATP-citrate lyase) occur in parallel with the changes in the extent of fatty acid formation, supporting the participation of this enzyme in lipogenesis. However, NADP-malate dehydrogenase, a potential source of reduced nucleotide coenzyme for lipogenesis in the adult, could not be detected in foetal rat liver.

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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

Biochemical Journal ◽

10.1042/bj1080705 ◽

1968 ◽

Vol 108 (5) ◽

pp. 705-713 ◽

Cited By ~ 22

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.

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Regulation of ATP-citrate lyase in primary cultures of adult rat hepatocytes.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)86444-x ◽

1979 ◽

Vol 254 (23) ◽

pp. 12169-12173

Author(s):

J.T. Spence ◽

H.C. Pitot ◽

G. Zalitis

Keyword(s):

Primary Cultures ◽

Rat Hepatocytes ◽

Atp Citrate Lyase ◽

Adult Rat ◽

Citrate Lyase ◽

Adult Rat Hepatocytes

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

Biochimica et Biophysica Acta (BBA) - General Subjects ◽

10.1016/0304-4165(68)90071-8 ◽

1968 ◽

Vol 158 (1) ◽

pp. 51-61 ◽

Cited By ~ 25

Author(s):

Yasushi Daikuhara ◽

Takuo Tsunemi ◽

Yoshiro Takeda

Keyword(s):

Rat Liver ◽

Atp Citrate Lyase ◽

Citrate Lyase

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

Biochemical Journal ◽

10.1042/bj1640119 ◽

1977 ◽

Vol 164 (1) ◽

pp. 119-123 ◽

Cited By ~ 36

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.

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Studies on ATP Citrate Lyase of Rat Liver

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a128474 ◽

1966 ◽

Vol 60 (5) ◽

pp. 543-553 ◽

Cited By ~ 63

Author(s):

HIDEO INOUE ◽

FUJIO SUZÚKI ◽

KEIHACHI FUKUNISHI ◽

KOZABURO ADACHI ◽

YOSHIRO TAKEDA

Keyword(s):

Rat Liver ◽

Atp Citrate Lyase ◽

Citrate Lyase

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

Biochemical Journal ◽

10.1042/bj1060321 ◽

1968 ◽

Vol 106 (2) ◽

pp. 321-329 ◽

Cited By ~ 78

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.

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