Ketohexokinase, isoenzymes of glucokinase and glycogen synthesis from hexoses in neonatal rat liver

Ballard, F. J.; Oliver, I.T.

doi:10.1042/bj0900261

Cited by 85 publications

(20 citation statements)

References 19 publications

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“…The change in the pattern of isoenzymes of lactate dehydrogenase during development has been demonstrated by Cahn, Kaplan, Levine & Zwilling (1962). Asimilarpattern has been observed in liver glucokinase (Walker, 1962;Ballard & Oliver, 1964).…”

Section: Discussionmentioning

confidence: 86%

“…The developmental pattern of liver ADH in the rat and the guinea pig shows a linear increase of activity throughout development and no postparturition peak is observed, as in many other enzymes such as tryptophan peroxidase (Nemeth, 1959), tyrosine transaminase (Sereni, Kenney & Kretchmer, 1959), some of the gluconeogenic enzymes (Ballard & Oliver, 1962) and the ureasynthesizing enzymes (Kennan & Cohen, 1959).…”

Section: Discussionmentioning

confidence: 99%

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Developmental changes in alcohol-dehydrogenase activity in rat and guinea-pig liver

Räihä¹,

Koskinen²,

Pikkarainen³

1967

Biochemical Journal

114

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1. Alcohol-dehydrogenase activity is first detectable in the rat foetus on about the eighteenth day of gestation, after which time it increases to about 25% of the adult activity at birth. Adult activity is reached at about 18 days after birth. The ethanol-oxidizing capacity of liver slices from rats correlates well with the increase of the enzyme activity in vitro. 2. In the guinea pig there is a steady linear increase from about 17 days before term to 5 days after birth. Adult activity is reached between the sixth and eighth postnatal day. 3. Some kinetic properties of liver alcohol dehydrogenase are very similar in newbom and adult rats. 4. Administration of ethanol to pregnant rats during the latter half of gestation had no effect on alcohol-dehydrogenase activity in the liver of the newbom offspring. Intraperitoneal injections of ethanol to newbom and young rats had no effect on the alcohol-dehydrogenase activity of the livers. 5. Intraperitoneal injections of hydrocortisone and triamcinolone to newbom and adult non-adrenalectomized rats had no significant effect on the increase of the alcohol-dehydrogenase activity as studied up to 4 days after the injection.

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Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Developmental changes in alcohol-dehydrogenase activity in rat and guinea-pig liver

Räihä¹,

Koskinen²,

Pikkarainen³

1967

Biochemical Journal

114

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“…Synthesis of glycogen from glucose and fructose has been demonstrated in rat fetal liver slices [7]. In the fetal rat, the enzyme glucokinase appears to be absent from liver, but glucose is actively phosphorylated through hexokinase activity [2]. Thus, the pathway for conversion of plasma glucose to glycogen in fetal liver has been demonstrated in vitro.…”

Section: Discussionmentioning

confidence: 90%

Glucose Metabolism in the Fetus in Utero: The Effect of Maternal Fasting and Glucose Loading in the Rat

Goodner

Thompson

1967

Pediatr Res

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ExtractPregnant rats during the last 3 days of gestation were fasted 16 hours, anesthetized and infused with glucose-U-C14 for two hours following a loading dose of labeled glucose. Rats infused with tracer only were compared with glucose-loaded rats. The volume of distribution for glucose was 28 % in the fasted rats and increased to 50% of body weight with glucose loading. Hepatic glucose production was 1.2 mg/min/300 g body weight in the fasted rats. This value was depressed to 0.32 with glucose loading. Comparison of maternal and fetal plasma after the two-hour infusion showed that the concentration of glucose in fetal plasma equaled the maternal in fasting rats and paralleled maternal hyperglycemia with a gradient (maternal to fetal) of 1.22 in the glucose-loaded rats. In the fasted rats, the specific activity of fetal plasma glucose was less than half that of maternal plasma glucose, indicating that unlabeled glucose was being produced within the conceptus. By contrast, the specific activities were more nearly equal in the glucose-loaded rats, showing that maternal plasma glucose was the primary source of fetal plasma glucose during hyperglycemia. The glycogen concentrations of fetal liver and placenta were not altered by glucose loading. The degree of labeling of glycogen was very small in fetal liver and placenta in fasting rats, while glucose loading increased the specific activity of glycogen in these two organs but the quantitative change in glycogen remained small compared to the total glycogen stores. However, with glucose loading, the incorporation of radioglucose into maternal liver glycogen reached 31 % of the liver glycogen store.From these data it is concluded that under conditions of fasting, the fetal liver contributes to the fetal plasma glucose through gluconeogenesis in preference to glycogenolysis, while in the presence of maternal hyperglycemia, fetal gluconeogenesis is reduced and glycogen synthesis in fetal liver is accelerated. SpeculationDuring fasting, a competition may develop for gluconeogenetic precursors between the maternal liver, the fetal liver and the growing fetal tissues. Because of such a competition, prolonged fasting or protein malnutrition could result in either reduced availability of fetal glucose or limitation of protein synthesis or both. During short periods of fasting, the store of glycogen in the fetal liver was neither mobilized nor significantly increased by synthesis from glucose, while with glucose loading, net synthesis increased. These data suggest that accumulation of fetal liver glycogen occurs as a stepwise cycle with net synthesis occurring only during feeding and relative retardation of glycogenolysis predominating during fasting.

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“…Ornithine aminotransferase was assayed by the method of Katunuma et al [27], tyrosine aminotransferase by that of Rosen et al [28], cystathionase by that of Matsuo and Greenberg [22], glucokinase by that of Ballard and Oliver [29] and aldolase by that of Blostein and Rutter [30]. Glucose-6-phosphate dehydrogenase was assayed by measuring the rate of increase in absorbance of NADPH at 25 "C [31].…”

Section: Preparation and Assay O J Substrate Enzymesmentioning

confidence: 99%

Crystallization and Properties of Cathepsin B from Rat Liver

1979

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Cathepsin B from rat liver was purified to apparent homogeneity by cell-fractionation, freezing and thawing, acetone treatment, gel filtration, DEAE-Sephadex and CM-Sephadex column chromatography, and was crystallized. The purified enzyme formed spindle-shaped crystals and its homogeneity was proved by disc gel electrophoresis in the presence of sodium dodecyl sulfate and by ultracentrifugical analysis.Its ~2 0 ,~ value was 2.8 S and its relative molecular mass was calculated to be 22 500 (k 900) by sedimentation equilibrium analysis. Crystalline cathepsin B was shown to consist of four isozymes with isoelectric points between pH 4.9 and 5.3, the main isozyme having an isoelectric point of pH 5.0. The enzyme was irreversibly inactivated by exposure to weak alkali. The pH optimum was 6.0 with a-N-benzoyl-~~-arginine-4-nitroanilide as substrate. Amino acid analysis showed that the enzyme contained hexosamine, glucosamine and galactosamine. Cathepsin B inactivated aldolase, glucokinase, apo-ornithine aminotransferase, and apo-cystathionase, but the rates of inactivation of glucokinase, apo-ornithine aminotransferase, and apocystathionase were lower than that of aldolase. Studies by polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate showed that cathepsin B degraded apo-ornithine aminotransferase to two polypeptide chains differing in relative molecular mass and electrophoretic mobility.Inhibitors of so-called cathepsin B reduce protein degradation in various experimental systems. This has been demonstrated with leupeptin in a system in vitro [l] and in tissue culture [2] and with chloroquine in tissue culture [3]. Therefore, it is thought that cathepsin B is important in intracellular protein degradation. Cathepsin B has been found in various mammalian tissues and its purification has been attempted by many workers. The preparation of cathepsin B of Greenbaum and Fruton [4] was demonstrated by Otto

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Ketohexokinase, isoenzymes of glucokinase and glycogen synthesis from hexoses in neonatal rat liver

Cited by 85 publications

References 19 publications

Developmental changes in alcohol-dehydrogenase activity in rat and guinea-pig liver

Developmental changes in alcohol-dehydrogenase activity in rat and guinea-pig liver

Glucose Metabolism in the Fetus in Utero: The Effect of Maternal Fasting and Glucose Loading in the Rat

Crystallization and Properties of Cathepsin B from Rat Liver

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