scholarly journals Pathways of fructose conversion into glucose in foetal rat liver

1965 ◽  
Vol 97 (2) ◽  
pp. 365-370 ◽  
Author(s):  
FJ Ballard
Keyword(s):  
Rat Liver ◽  
Specific Activity ◽  
High Specific Activity ◽  
Direct Conversion ◽  
Seminal Vesicles ◽  
Adult Liver ◽  
Adult Rats ◽  
Liver Slices ◽  
Foetal Rat ◽  
Glucose Formation

1. Glucose, formed from [1-(14)C]fructose or [6-(14)C]fructose in rat-liver slices, has been isolated as gluconate and degraded to give the radioactivity in C-1, C-2-5 and C-6. 2. By using this method it has been shown that, in liver from foetal rats younger than 20 days, glucose is formed from fructose without splitting of the molecule by the aldolase reaction. The rate of glucose formation from fructose in liver from these foetuses is approximately half of the rate in adult liver. 3. The direct conversion of fructose into glucose in foetal rat liver is not via sorbitol as in seminal vesicles, as this pathway cannot be detected. 4. When liver slices are incubated with [U-(14)C]fructose of high specific activity, the labelled intermediates are similar whether from liver from 18-day foetal, newborn or adult rats. 5. These findings are discussed with reference to the changing pathways of fructose metabolism during perinatal development of the liver in the rat.

Biosynthesis of 1,2-3H and 4-14C steroid sulfates of high specific activity

1970 ◽  
Vol 48 (1) ◽  
pp. 148-150 ◽  
Author(s):  
J. Torday ◽  
G. Hall ◽  
M. Schweitzer ◽  
C. J. P. Giroud
Keyword(s):  
Rat Liver ◽  
Specific Activity ◽  
Liver Homogenate ◽  
High Specific Activity ◽  
Supernatant Fraction ◽  
Metabolic Studies

A supernatant fraction of rat liver homogenate enriched with ATP was used for the biosynthesis of the ester sulfates of several 3H and 14C steroids of the pregn-4-ene series. The method provides a simple means to prepare steroid sulfates of high specific activity for use in either metabolic studies or as reference compounds in the quantification of such conjugates by isotope assays.

Developmental pattern of glucuronide formation in rat and guinea pig liver

1963 ◽  
Vol 205 (4) ◽  
pp. 663-666 ◽  
Author(s):  
Lawrence M. Gartner ◽  
Irwin M. Arias
Keyword(s):  
Guinea Pigs ◽  
Wistar Rats ◽  
Newborn Rats ◽  
Adult Liver ◽  
Adult Rats ◽  
Pig Liver ◽  
Liver Slices ◽  
Rat Liver Cells ◽  
Old Rats ◽  
Guinea Pig Liver

o-Aminophenol (OAP) glucuronide formation by liver slices from fetal and newborn Wistar rats up to 70 hr old is equivalent to or greater than OAP glucuronide formation by liver slices from adult rats. OAP glucuronide formation by homogenates of liver from 3-day-old rats, and slices or homogenates of liver from 3-day-old guinea pigs is substantially less than that observed in comparable preparations of adult liver. These observations suggest that glucuronidation is deficient in newborn guinea pigs but not in newborn rats. Although the mechanisms responsible for these differences are unknown, the possibility is discussed that disruption of rat liver cells reduces glucuronide formation by activation of an inhibitor.

scholarly journals Development of adenylate kinase isoenzymes in rat liver

1971 ◽  
Vol 122 (4) ◽  
pp. 553-555 ◽  
Author(s):  
R. Filler ◽  
W. E. Criss
Keyword(s):  
Rat Liver ◽  
Liver Cell ◽  
Adenylate Kinase ◽  
Energy Flow ◽  
Kinase Activity ◽  
Adult Liver ◽  
Foetal Liver ◽  
Foetal Rat ◽  
Wet Weight ◽  
Developing Rat

Total adenylate kinase activity was determined in developing rat liver. The activity was 18 units/g wet weight of tissue in foetal liver; this increased to 41 units/g immediately after birth and continued increasing until adult activities of 150 units/g were reached after two weeks. The adenylate kinase activity was separated into four isoenzymes. Only isoenzymes II and III were observed in foetal rat liver. Isoenzyme II activity was 2 units/g in the foetal liver and increased to 25 units/g in adult liver. Adenylate kinase III activity was 20 units/g in the foetal liver and increased to 118 units/g in adult liver. The possible role that adenylate kinase might have in regulating the energy flow in the developing liver cell is discussed.

THE EFFECT OF GROWTH HORMONE ON THE UTILIZATION OF 1-C14OCTANOIC ACID BY RAT LIVER SLICES

1957 ◽  
Vol 35 (1) ◽  
pp. 497-502
Author(s):  
W. F. Perry ◽  
H. G. Friesen
Keyword(s):  
Growth Hormone ◽  
Fatty Acid ◽  
Octanoic Acid ◽  
Specific Activity ◽  
Carbon Dioxide Production ◽  
Acetoacetic Acid ◽  
Adult Rats ◽  
Liver Slices ◽  
Old Rats ◽  
Ad Libitum

Young ([Formula: see text] months), adult (4–5 months), and old (2(+) years) rats were injected with growth hormone intraperitoneally in doses of 4 mg./100 g. at various intervals of time before removal of the liver. Slices of liver were incubated with radioactive octanoic acid and the production of CO2and acetoacetic acid measured.In adult rats fed ad libitum, growth hormone injected 4 hours before the rats were killed had no consistent effect on acetoacetic acid or carbon dioxide production by the liver slices. In adult rats fasted 24 hours before they were killed, growth hormone was likewise found to have no effect on ketogenesis and CO2production irrespective of whether it was injected 4, 12, or 24 hours before the rats were killed. Young rats that were fasted 24 hours and to which growth hormone was administered at the 20th hour of fasting showed a slight ketogenesis but the values for the specific activity of the acetoacetic acid suggested the increased ketogenesis was not derived from the labelled fatty acid. No effect on CO2production was noted. In old rats that were fasted 24 hours and to which growth hormone was given at the 20th hour of fasting, a slight decrease in acetoacetic acid formation by the liver slices was observed which appeared to be due to an over-all reduction in fatty acid utilization. There was again no alteration in CO2production. Treatment of adult rats for 5 days with growth hormone, followed by incubation of the liver slices with octanoate, was found to influence neither ketogenesis nor CO2production.

THE EFFECT OF GROWTH HORMONE ON THE UTILIZATION OF 1-C14OCTANOIC ACID BY RAT LIVER SLICES

1957 ◽  
Vol 35 (7) ◽  
pp. 497-502 ◽  
Author(s):  
W. F. Perry ◽  
H. G. Friesen
Keyword(s):  
Growth Hormone ◽  
Fatty Acid ◽  
Octanoic Acid ◽  
Specific Activity ◽  
Carbon Dioxide Production ◽  
Acetoacetic Acid ◽  
Adult Rats ◽  
Liver Slices ◽  
Old Rats ◽  
Ad Libitum

Young ([Formula: see text] months), adult (4–5 months), and old (2(+) years) rats were injected with growth hormone intraperitoneally in doses of 4 mg./100 g. at various intervals of time before removal of the liver. Slices of liver were incubated with radioactive octanoic acid and the production of CO2and acetoacetic acid measured.In adult rats fed ad libitum, growth hormone injected 4 hours before the rats were killed had no consistent effect on acetoacetic acid or carbon dioxide production by the liver slices. In adult rats fasted 24 hours before they were killed, growth hormone was likewise found to have no effect on ketogenesis and CO2production irrespective of whether it was injected 4, 12, or 24 hours before the rats were killed. Young rats that were fasted 24 hours and to which growth hormone was administered at the 20th hour of fasting showed a slight ketogenesis but the values for the specific activity of the acetoacetic acid suggested the increased ketogenesis was not derived from the labelled fatty acid. No effect on CO2production was noted. In old rats that were fasted 24 hours and to which growth hormone was given at the 20th hour of fasting, a slight decrease in acetoacetic acid formation by the liver slices was observed which appeared to be due to an over-all reduction in fatty acid utilization. There was again no alteration in CO2production. Treatment of adult rats for 5 days with growth hormone, followed by incubation of the liver slices with octanoate, was found to influence neither ketogenesis nor CO2production.

scholarly journals Precocious development of cytochrome P-450 in neonatal rat liver after glucocorticoid treatment

1979 ◽  
Vol 182 (1) ◽  
pp. 233-235 ◽  
Author(s):  
J E A Leakey ◽  
J R Fouts
Keyword(s):  
Rat Liver ◽  
Neonatal Rat ◽  
Adult Liver ◽  
Glucocorticoid Treatment ◽  
Early Postnatal Development ◽  
Liver Cytochrome ◽  
Foetal Rat ◽  
Cytochrome P 450 ◽  
Precocious Development ◽  
Hepatic Cytochrome

Intraperitoneal injection of neonatal rats with glucocorticoid hormones causes precocious development of hepatic cytochrome P-450. Glucagon injection fails to stimulate this cytochrome P-450 development. Adult liver cytochrome P-450 is less responsive to glucocorticoid stimulation than is that of neonatal rat liver. Adrenalectomy of prematurely delivered neonatal animals prevents the early postnatal development of cytochrome P-450. Glucocorticoids failed to increase cytochrome P-450 concentrations in foetal rat liver. These findings imply that, although glucocorticoids are mandatory regulatory factors controlling cytochrome P-450 development, they are not themselves the ‘trigger’ initiating onset of that development.

scholarly journals Changes in lipid synthesis in rat liver during development

1967 ◽  
Vol 102 (3) ◽  
pp. 952-958 ◽  
Author(s):  
F. J. Ballard ◽  
R. W. Hanson
Keyword(s):  
Rat Liver ◽  
Lipid Synthesis ◽  
Adult Liver ◽  
Atp Citrate Lyase ◽  
Adult Rat ◽  
Potential Source ◽  
Liver Slices ◽  
Citrate Lyase ◽  
Glucose Incorporation ◽  
Cleavage Enzyme

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.

scholarly journals The role of glycogen synthase phosphatase in the glucocorticoid-induced deposition of glycogen in foetal rat liver

1980 ◽  
Vol 192 (2) ◽  
pp. 607-612 ◽  
Author(s):  
F Vanstapel ◽  
F Doperé ◽  
W Stalmans
Keyword(s):  
Rat Liver ◽  
Glycogen Synthase ◽  
Glycogen Synthesis ◽  
Late Gestation ◽  
Adult Liver ◽  
Foetal Liver ◽  
Foetal Rat ◽  
Experimental Approaches ◽  
Protein Components

1. The mechanism that underlies the induction of glycogen synthesis in the foetal rat liver by glucocorticoids was reinvestigated in conditions where the accumulation of glycogen is either precociously induced with dexamethasone or inhibited by steroid deprivation. It appears that glucocorticoids act as the physiological trigger for glycogen synthesis by inducing both glycogen synthase (a known effect) and its activating enzyme, glycogen synthase phosphatase. 2. The activity of glycogen synthase phosphatase in adult liver stems from the interaction of two protein components [Doperé, Vanstapel & Stalmans (1980) Eur. J. Biochem. 104, 137–146]. Two independent experimental approaches indicate that the cytosolic ‘S-component’ is already well developed in the foetal liver before the onset of glycogen synthesis. The manifold glucocorticoid-dependent increase in synthase phosphatase activity during late gestation must be attributed to the specific development of the glycogen-bound ‘G-component’.

scholarly journals Biosynthesis of microsomal nicotinamide–adenine dinucleotide phosphate–cytochrome c reductase by membrane-bound and free polysomes from rat liver

1969 ◽  
Vol 112 (2) ◽  
pp. 139-147 ◽  
Author(s):  
G. Ragnotti ◽  
G. R. Lawford ◽  
P. N. Campbell
Keyword(s):  
Endoplasmic Reticulum ◽  
Rat Liver ◽  
Specific Activity ◽  
Reductase Activity ◽  
Gel Filtration ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
High Specific Activity ◽  
Rat Liver Cells ◽  
Microsome Fraction ◽  
Membrane Bound

1. NADPH–ferricytochrome c oxidoreductase (EC 1.6.2.3) was purified from the endoplasmic reticulum of rat liver cells. The methods, which involved digestion of membrane with Steapsin, a crude pancreatic extract containing diastase and trypsin, gel filtration and preparative electrophoresis on polyacrylamide, provided an enzyme with a high specific activity in good yield. 2. The incorporation of 14C-labelled amino acids into the purified reductase by the incubation of various subcellular fractions was studied. The microsome fraction, bound polysomes, free polysomes and detergent-treated polysomes effected the synthesis of the enzyme. 3. The reductase that had been synthesized by the polysomes was tightly bound to preparations of smooth-surfaced endoplasmic reticulum that were added to the incubation medium. 4. Reductase activity could be detected on both free and detergent-treated polysomes. Evidence is presented to show that this activity was due, at least in part, to the presence on the ribosomes of nascent enzyme. The association of enzyme with detergent-treated polysomes did not appear to be due to contamination of the ribosomes with either membrane or cell sap but it is possible for such ribosomes to adsorb some enzyme. 5. The amount of reductase activity associated with the detergent-treated polysomes was increased when the rats from which the polysomes were derived had been previously injected with phenobarbitone. 6. The results are discussed with respect to their relevance for the question of the existence of two functionally different groups of polysomes in the liver and for current ideas on the biogenesis of membranes.

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.

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