Effect of insulin on glycogen metabolism in isolated catfish hepatocytes

Ottolenghi, C; Puviani, A.C.; Baruffaldi, A.; Brighenti, L

doi:10.1016/0300-9629(84)90620-0

Cited by 25 publications

(5 citation statements)

References 22 publications

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“…summer vs. winter and spring). Alternatively, glucose may be necessary for insulin action on glycogen metabolism in the rat liver (Ottolenghi et al 1984), and the higher glucose concentrations resulting from the greater glycogen depletion rates may be potentiating insulin action. Further studies using cell systems where glucose levels and glycogen depletion rates can be controlled are required to determine the interactions of glucose, glycogen, and hormones in the regulation of glycogen metabolism.…”

Section: Discussionmentioning

confidence: 99%

The role of glycogen phosphorylase in the regulation of glycogenolysis by insulin and glucagon in isolated eel (Anguilla rostrata) hepatocytes

Foster

Moon

1990

Fish Physiol Biochem

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The effects of porcine, scombroid, and salmon insulins, and bovine and anglerfish glucagons on glycogen depletion and glycogen phosphorylase (GPase) activities were examined in freshly isolated American eel (Anguilla rostrata) hepatocytes. Eel liver GPase in crude homogenates was activated (increase in % GPase a) by phosphorylating conditions and was rapidly inactivated (less than 1 h) when a phosphatase inhibitor (fluoride) was absent. Caffeine inhibits, and AMP activates, the b form of GPase consistent with their effects on rat liver GPase. Both mammalian and fish glucagons increased glucose production in eel hepatocytes, but had more ambiguous effects on glycogen levels and GPase activities. The magnitude of bovine glucagon effects were dependent on the initial glycogen content of the cells; only at glycogen concentrations less than approximately 70 μmoles.g(-1) did glucagon significantly increase % GPase a. Anglerfish glucagon significantly increased cyclic AMP (cAMP) concentrations by 90% at 10(-7) M, but had no effects at 10(-9) M and 10(-8) M. Scombroid and salmon insulins maintained hepatocyte glycogen concentrations and decreased glucose production, with these effects more pronounced at low (10(-9) to 10(-8) M) rather than high (10(-7) M) hormone concentrations. Porcine and salmon insulins decreased total GPase and % GPase a activities, and salmon insulin decreased CAMP levels, but only at 10(-8) M (by 44%).Glycogen is, therefore, depleted by glucagon and maintained by insulin in freshly isolated American eel hepatocytes, and these changes are accomplished, at least in part, by changes in the activities of GPase. Changes in cAMP do not explain all of the observed hormone effects.

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Section: Discussionmentioning

confidence: 99%

The role of glycogen phosphorylase in the regulation of glycogenolysis by insulin and glucagon in isolated eel (Anguilla rostrata) hepatocytes

Foster

Moon

1990

Fish Physiol Biochem

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“…The hepatocyte preparation was performed as reported elsewhere (Ottolenghi et al 1984a). Hepatocytes (about 100 mg of wet weight corresponding to about 2 • 106 cells) were suspended in 2.5 ml of teleost-Ringer solution, pH 7.4.…”

Section: T-iepatocyte Preparation and Incubationmentioning

confidence: 99%

Glycogenolytic action of glucagon-family peptides and epinephrine on catfish hepatocytes

Ottolenghi

Puviani

Gavioli

et al. 1989

Fish Physiol Biochem

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Glycogenolytic effects of salmon and mammalian glucagons, salmon glucagon-like peptide (GLP) and epinephrine were studied on liver cells isolated from catfish (Ictalurus melas). In spring and summer, salmo-glucagon (3×10(-10) to 3×10(-8) M) was more effective than its mammalian counterpart in the stimulation of glucose release and cAMP synthesis in hepatocytes. GLP was less potent as compared to both glucagons. γ-amylase activity was not affected by the treatment with either glucagon-family peptides or epinephrine.The comparison of the glycogenolytic effects of salmon glucagon to those of epinephrine reveals a greater potency of the latter hormone in the stimulation of cAMP synthesis, glycogen-phosphorylase activity and glucose release. Glycogen content in the liver cells was equally depleted after treatment with both of the two hormones.

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“…VP to HV perfusion was designed to destroy selectively PP cells and to obtain an enriched population of PV hepatocytes, whereas HV to VP perfusion destroyed selectively PV cells and produced a population enriched with PP hepatocytes. Cells from the part of the liver that remained undisrupted by digitonin were isolated by conventional collagenase (0.2 mg/mL) digestion, as described elsewhere (Ottolenghi et al 1984). The cell yield was about 30% of the liver weight.…”

Section: Isolation Of Hepatocyte Populations Enriched In Either Pp Ormentioning

confidence: 99%

Separation of two populations of fish hepatocytes by digitonin infusion: some metabolic patterns and hormonal responsiveness

Ottolenghi¹,

Ricci²,

Gavioli³

et al. 1991

Can. J. Zool.

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1991. Separation of two populations of fish hepatocytes by digitonin infusion: some metabolic patterns and hormonal responsiveness. Can. J. Zool .69: 427-435. Two pools of liver cells, enriched either in periportal or in perivenous hepatocytes, were obtained from the catfish Ictalurus melas by the selective destruction of the liver by digitonin infusion. Following digitonin pulses directed either orthograde via the portal vein or retrograde via the hepatic vein, hepatocytes from undamaged perivenous and periportal zones, respectively, were isolated by the conventional collagenase perfusion procedure. Eluates from either periportal or perivenous zones were collected for a total of 9 min before, during, and immediately following the digitonin pulse. The eluates were assayed for protein, glycogen, glucose, and activities of lactate dehydrogenase and alanine aminotransferase, and their yield ("recovery") was estimated as a percentage of the total hepatic content. The aforementioned metabolic compounds and enzyme activities were measured also in periportalend perivenous liver cells. No significant differences were obtained between these cells. Both pools of hepatocytes were more than 90% viable and remained hormone responsive. Epinephrine (3 X lop8 M) or salmon glucagon (3 x M) elevated CAMP content, and stimulated glycogen phosphorylase a activity, glycogen depletion , and glucose release in periportal and perivenous liver cells. No differences were observed between periportal and perivenous cells in their metabolic responsiveness to either hormone. OTTOLENGHI, C., RICCI, D., GAVIOLI, M. E., PUVIANI, A. C., FABBRI, E., CAPUZZO, A., BRIGHENTI, L., et PLISETSKAYA, E. M. 1991. Separation of two populations of fish hepatocytes by digitonin infusion: some metabolic patterns and hormonal responsiveness.Can. J. Zool. 69 : 427-435. Deux populations de cellules hkpatiques, enrichies d'hkpatocytes pkriportaux ou pkriveineux, ont kt6 obtenues chez Ictalurus melas par destruction selective du foie par infusion de digitonine. Aprks une courte infusion de digitonine en direction orthograde, via la veine portale, ou rktrograde, via la veine hkpatique, les hkpatocytes intacts des zones Nriveineuse et @riportale ont kt6 isolks par un traitement classique a la collagknase. Des klutriats de la zone @riportale ou de la zone griveineuse ont kt6 recueillis durant 9 min avant, pendant ou immkdiatement aprks le traitement a la digitonine. Les fractions protkine, glycogkne et glucose de mCme que I'activitk des enzymes lactate dCshydrogknase et alanine-aminotransfkrase, ont kt6 analyskes et leur production (fraction rkcupkrke), estimke en pourcentage de leur concentration totale dans le foie. Les produits de mktabolisme et activitks enzymatiques mentionnks ci-haut ont kgalement kt6 mesurks dans les cellules hkpatiques firiportales et pkriveineuses. I1 n'y avait pas de diffkrences significatives entre ces cellules. Les deux populations d'hkpatocytes se sont avkrkes viables a 90% et sont restkes sensibles a I'action des hormones. De l'kpinkphri...

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Effect of insulin on glycogen metabolism in isolated catfish hepatocytes

Cited by 25 publications

References 22 publications

The role of glycogen phosphorylase in the regulation of glycogenolysis by insulin and glucagon in isolated eel (Anguilla rostrata) hepatocytes

The role of glycogen phosphorylase in the regulation of glycogenolysis by insulin and glucagon in isolated eel (Anguilla rostrata) hepatocytes

Glycogenolytic action of glucagon-family peptides and epinephrine on catfish hepatocytes

Separation of two populations of fish hepatocytes by digitonin infusion: some metabolic patterns and hormonal responsiveness

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