Glycolytic isoenzymes and glycogen metabolism in regenerating liver from rats on controlled feeding schedules

Bonney, Robert J.; Hopkins, Harold A.; Walker, P. Roy; Potter, Van R.

doi:10.1042/bj1360115

Cited by 51 publications

(24 citation statements)

References 14 publications

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“…The glycogen content declined transiently after hepatectomy (Fig. 2), in agreement with other studies (Simek et al, 1968;Bonney et al, 1973). There were no major changes in the concentration of plasma unesterified fatty acids or triacylglycerols compared with shamoperated controls (Fig.…”

Section: Concentration Ofliver Glycogen Andplasma Lipidssupporting

confidence: 81%

Fatty acid synthesis in the regenerating liver of the rat

Gove¹,

Hems²

1978

Biochemical Journal

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1. Synthesis de novo of fatty acids in the rat liver, measured per g wet wt. of tissue, was increased by a factor of about two, between 1 and 4 days after partial hepatectomy, compared with rates in sham-operated control rat livers. 2. There were no associated changes in the rates ofliver cholesterol synthesis or of adipose-tissue fatty acid synthesis in rats after partial hepatectomy, compared with rates in sham-operated rats. 3. In regenerating livers, perfused under three different conditions, there was no alteration in the capacity for fatty acid synthesis compared with that of control rats. 4. The increased synthesis of fatty acids in regenerating liver was associated with insignificant increases in plasma concentrations oftriacylglycerols and free fatty acids, with a decrease in content of liver glycogen, and with no change in hepatic activity of acetyl-CoA carboxylase. 5. The accelerated rate ofsynthesis offatty acids in regenerating liver appears not to be due to any intrinsic alteration in hepatic capacity for fatty acid synthesis, but it may be caused by the continuous action on liver of unidentified circulating factors.

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Section: Concentration Ofliver Glycogen Andplasma Lipidssupporting

confidence: 81%

Fatty acid synthesis in the regenerating liver of the rat

Gove¹,

Hems²

1978

Biochemical Journal

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“…The onset and elevation of Kisozyme activity was accompanied by the secondary decline to negligible levels of the L form. As the cell population entered stationary phase on day 9, K-form activity reached peak levels disproportionately higher than net increases in cell numbers and considerably higher than peak levels reported for 48-hr regenerating liver (32). K-isozyme levels began to fall slowly by day 10 but, unlike the L form, failed to approach initial values by day 12. al-Fetoprotein production was not detected during the early phases of the in vitro growth cycle (Fig.…”

Section: Methodsmentioning

confidence: 91%

Growth state-dependent phenotypes of adult hepatocytes in primary monolayer culture.

Leffert¹,

Moran²,

Sell³

et al. 1978

Proc. Natl. Acad. Sci. U.S.A.

109

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A proliferation-competent adult rat liver cell monolayer system has been analyzed for tissue-specific functions during its growth cycle. High levels of the adult (L type) form of pyruvate kinase (EC 2.7.1.40) and glutathione S-transferase B ("ligandin," EC 2.5.1.18) are observed during the early lag phase; they decline markedly during the logarithmic phase and reappear during the stationary phase. By contrast, elevated levels ofthe fetal (K type) form of pyruvate kinase and ai-fetoprotein production appear only after proliferation begins; this pattern diminishes slightly during stationary phase as the adult phenotype is restored. Albumin production continues throughout the entire growth cycle. These in vitro findings simulate those observed during hepatoproliferative transitions in the intact animal and, as such, constitute a developmental program for normal epithelial cells in primary culture. Many specialized animal cell functions are related to proliferative and developmental states (for review, see ref. 1). Much of this evidence comes from physiological studies of the liver (2-5). For example, the L-isozymic form of pyruvate kinase (EC 2.7.1.40) (6) and glutathione S-transferase B ("ligandin," EC 2.5.1.18) (7) are prominent hepatocyte properties associated with quiescent or adult states whereas the production of alfetoprotein (8) and the K-isozymic form of pyruvate kinase (6) are properties associated with proliferating or fetal states. Temporal aspects of the appearance or disappearance of differentiated properties during transitional states imply that distinct regulatory "programs" exist. However, the molecular and cellular bases of such programs are poorly understood and difficult to study in the intact animal. Hepatocyte tissue cultures offer a more direct approach (9) (15,16). Additional functional and proliferative properties of this system have been reported (9,15,17).Pyruvate Kinase Isozymes. At indicated times, culture media were removed and monolayers (10-20 dishes per point) were washed three times with 2 ml of ice-cold 10 mM phosphate-buffered saline, pH 7.0. Attached cells were scraped with a rubber policeman into 10 mM potassium phosphate, pH 7.0/5 mM magnesium sulfate/0.5 mM dithiothreitol/10% (vol/vol) glycerol and sonicated twice for 30 sec (Branson sonifier set at 50 W). Particulate material was removed by centrifugation at 100,000 X g at 40 for 1 hr. Total activity in high-speed supernatants was measured by using the coupled lactate dehydrogenase assay (18). The two different isozyme forms were measured by: (i) differential kinetic assay, based upon greater sensitivity of K-isozyme to inhibition by tryptophan (19) and (if) separation on DEAE-cellulose columns that, under the conditions used, bind only the L-isozymic form (20). Supernatant aliquots were applied to columns (10 X 0.6 cm), the K form was eluted with additional buffer, and the bound L form was eluted with buffer containing either 0.5 M KCl or with a 0-0.5 M KCl gradient. Enzyme activity and protein concentrations in co...

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“…Also, it does not appear that the increase in PFK-2/FBPase-2 mRNA was a result of the fasted/refed condition, because it has been shown that hepatectomized animals eat, albeit less, during the regeneration process (ref. 45 and data not shown). These results indicate that the changes in the PFK-2/FBPase-2 mRNA levels during liver regeneration are not dependent on the nutritional state of the animals.…”

Section: Discussionmentioning

confidence: 99%

Transcriptional and posttranscriptional regulation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase during liver regeneration.

Rosa

Tauler

Lange

et al. 1992

Proc. Natl. Acad. Sci. U.S.A.

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The control of 6-phosphofructo-2-kinase/ fructose-2,6-bisphosphatase (PFK-2/FBPase-2; EC 2.7.1.105/3.1.3.46) gene expression during liver regeneration was studied. The level of PFK-2/FBPase-2 mRNA decreased to about 5% of the control value 6 hr after partial hepatectomy. Thereafter the mRNA increased to a maximum at 48 hr and returned to normal levels by 96 hr. In sham-operated animals, only a small increase was observed during the first 4 hr. The mRNA was recognized by a 299-base-pair liver-specific cDNA probe but not by a muscle-specific probe. The time course of mRNA modulation was well correlated with PFK-2/FBPase-2 activity and with the amount of bifunctional enzyme protein determined by immunobo with an antibody raised against the N-terminal decapeptide of liver PFK-2/FBPase-2. No alteration in the degradation rate of PFK-2/FBPase-2 mRNA was noted after partial hepatectomy. The modulation of PFK-2/FBPase-2 gene expression during liver regeneration involved changes in the transcription rate. The rate decreased by 50% at 6 hr after liver resection. The rate increased thereafter to a maximum at 72 hr and then returned to control values by 96 hr. The transcription rate of albumin did not change, whereas that of phosphoenolpyruvate carboxykinase increased 12-fold at 6 hr. These results show that PFK-2/FBPase-2 gene transcription is specifIcally regulated and that this regulation is in part responsible for the alterations in hepatic metabolism seen in regenerating liver.

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Glycolytic isoenzymes and glycogen metabolism in regenerating liver from rats on controlled feeding schedules

Cited by 51 publications

References 14 publications

Fatty acid synthesis in the regenerating liver of the rat

Fatty acid synthesis in the regenerating liver of the rat

Growth state-dependent phenotypes of adult hepatocytes in primary monolayer culture.

Transcriptional and posttranscriptional regulation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase during liver regeneration.

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