Heterogeneous reciprocal localization of fructose‐1,6‐bis‐phosphatase and of glucokinase in microdissected periportal and perivenous rat liver tissue

Katz, Norbert; Teutsch, Harald F.; Jungermann, Kurt; Sasse, D.

doi:10.1016/0014-5793(77)81021-1

Cited by 120 publications

(51 citation statements)

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confidence: 99%

“…The periportal hepatocytes are rich in the glucose-forming enzymes glucose-6-phosphatase [5, 61, fructose-l,6-bisphosphatase [7, 81, phosphoenolpyruvate carboxykinase (PCK) [9 -1 I], alanine aminotransferase [I21 and tyrosine aminotransferase [12]. The perivenous cells are rich in the glucose-utilizing enzymes glucokinase [7,13,141 and pyruvate kinase L [9,15]. Evidence that the periportal cells are predominantly gluconeogenic and the perivenous cells glycolytic comes from studies in vivo and in vitro: zonal flux differences were calculated from enzyme and metabolite distributions measured in vivo [16].…”

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confidence: 99%

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Modulation by oxygen of the glucagon‐dependent activation of the phosphoenolpyruvate carboxykinase gene in rat hepatocyte cultures

Hellkamp

Christ

Bastian

et al. 1991

European Journal of Biochemistry

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In liver phosphoenolpyruvate carboxykinase (PCK) activity, protein and mRNA are localized predominantly in the periportal zone. The activation of the PCK gene by glucagon was studied in primary rat hepatocyte cultures under physiological arterial and venous oxygen tensions [16% and 8% (by vol.)]. PCK gene expression was monitored on the level of transcription, mRNA abundance and enzyme activity as well as enzyme synthesis and degradation.1. Transcription of the PCK gene was increased by 10 nM glucagon maximally after 0.5 h; it reached nearly basal levels again after 2 h. The increase in transcription was 45% lower under 8% oxygen than under 16% oxygen.2. PCK mRNA was maximally increased after 2 h under 16% oxygen and after 4 h under 8% oxygen; it subsequently declined to twice the basal values after 8 h. The maximal increase after 2 h was 50% lower under 8 % oxygen than under 16% oxygen.3. PCK enzyme activity was maximally increased after 4 -6 h. The maximal enhancement after 4 h was 50% lower under 8% oxygen than under 16% oxygen.4. The increase in PCK enzyme activity was due to an enhanced synthesis rate of PCK protein. The rate increase after 3 h was 35% lower under 8% oxygen than under 16% oxygen.5. The degradation of PCK protein was equal under both oxygen tensions.The results show that in cultured rat hepatocytes the induction of PCK gene expression is modulated by physiological concentrations of oxygen. The modulation occurred at the level of gene transcription, mRNA abundance, enzyme protein synthesis and enzyme activity. The periportal to perivenous oxygen gradient could be the major factor responsible for the predominant expression of the PCK gene in the periportal zone.Hepatocytes from the periportal (afferent) and perivenous (efferent) zones of the liver parenchyma differ in their content of enzymes and subcellular structures (reviews [1][2][3][4]). The periportal hepatocytes are rich in the glucose-forming enzymes glucose-6-phosphatase [5, 61, fructose-l,6-bisphosphatase [7, 81, phosphoenolpyruvate carboxykinase (PCK) [9 -1 I], alanine aminotransferase [I21 and tyrosine aminotransferase [12]. The perivenous cells are rich in the glucose-utilizing enzymes glucokinase [7,13,141 and pyruvate kinase L [9,15]. Evidence that the periportal cells are predominantly gluconeogenic and the perivenous cells glycolytic comes from studies in vivo and in vitro: zonal flux differences were calculated from enzyme and metabolite distributions measured in vivo [16]. They were observed in periportal-like and perivenous-like hepatocytes in

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confidence: 99%

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confidence: 99%

Modulation by oxygen of the glucagon‐dependent activation of the phosphoenolpyruvate carboxykinase gene in rat hepatocyte cultures

Hellkamp

Christ

Bastian

et al. 1991

European Journal of Biochemistry

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“…The major question raised by this study is why the zonal patterns of phosphorylation of at least certain enzymes (fructose 1,6-bisphosphatase, fructose 6-phosphate 2-kinase, pyruvate kinase and glycogen phosphorylase) do not coincide with the reported zonal distributions of their activities. Fructose 1,6-bisphosphatase and pyruvate kinase, for example, are reported, respectively, to be largely, but not exclusively, periportal (60-78%) and perivenous (55%) in location [2,12,[18][19][20][21]. whereas our results indicate that their phosphorylation is exclusively periportal or perivenous, respectively (Table 1).…”

Section: Discussionmentioning

confidence: 43%

Glucagon stimulates phosphorylation of different peptides in isolated periportal and perivenous hepatocytes

Aggarwal

Ko²,

1995

FEBS Letters

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The perivenous and periportal zones of the liver acinus differ in enzyme complements and capacities for gluconeogenesis, glycolysis and other metabolic processes. The biochemical factors governing this metabolic zonation are still poorly understood. Glueagon-mediated protein phosphorylation is an important factor in the regulation of hepatic metabolism. Here we show, by comparing the 32P-lahelling pattern of isolated periportal and perivenous hepatocytes, that glucagon promotes the phosphorylation of zone-specific peptides as well as three common peptides (glycogen phosphorylase, glycogen synthase and pyruvate kinase) in the two cell types. We propose that the zone-specific phosphorylation of peptides is an important factor governing the shortterm zonation of metabolic processes in the liver.

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“…Conversely, there is a high activity of key glycolytic enzymes in the perivenous zone: glucokinase and pyruvate kinaseL (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Our results indicate a correlation between expression of the erythroid/ brain GT and cells using glucose as a carbon source via glycolysis.…”

Section: Discussionmentioning

confidence: 72%

Restricted expression of the erythroid/brain glucose transporter isoform to perivenous hepatocytes in rats. Modulation by glucose.

Tal¹,

Schneider²,

Thorens³

et al. 1990

J. Clin. Invest.

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The "erythroid/brain" glucose transporter (GT) isoform is expressed only in a subset of hepatocytes, those forming the first row around the terminal hepatic venules, while the "liver" GT is expressed in all hepatocytes. After 3 d of starvation, a threeto fourfold elevation of expression of the erythroid/brain GT mRNA and protein is detected in the liver as a whole; this correlates with the expression of this GT in more hepatocytes, those forming the first three to four rows around the hepatic venules. Starvation-dependent expression of the erythroid/ brain GT on the plasma membrane of these additional hepatocytes is lost within 3 h of glucose refeeding; however, by immunoblotting we show that the protein is still present. Its loss from the surface is possibly explained by internalization. (J.Clin. Invest. 1990. 86:986-992.) Key words: starvation * liver glucose transporter * glucose refeeding * regulation and internalization Introduction The liver plays a key role in glucose homeostasis. Of the blood entering the liver, 75% comes from the digestive system via the portal vein and 25% from the hepatic artery. During passage of blood through the liver, glucose in excess of 5 mM (after a meal) is removed; it is either stored as glycogen or catabolized by glycolysis. Between meals and during starvation, when blood glucose is lower then 5 mM, hepatic glycogen degradation and gluconeogenesis result in release of glucose into the blood. Thus, constant blood glucose concentration is maintained by the parenchymal cells (hepatocytes).

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Heterogeneous reciprocal localization of fructose‐1,6‐bis‐phosphatase and of glucokinase in microdissected periportal and perivenous rat liver tissue

Cited by 120 publications

References 23 publications

Modulation by oxygen of the glucagon‐dependent activation of the phosphoenolpyruvate carboxykinase gene in rat hepatocyte cultures

Modulation by oxygen of the glucagon‐dependent activation of the phosphoenolpyruvate carboxykinase gene in rat hepatocyte cultures

Glucagon stimulates phosphorylation of different peptides in isolated periportal and perivenous hepatocytes

Restricted expression of the erythroid/brain glucose transporter isoform to perivenous hepatocytes in rats. Modulation by glucose.

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