Mitogenic effect of sodium phenobarbital and rat liver arginase activity

Résumé Au cours de la régénération du foie normal des rats, on a constaté une augmentation — statistiquement significative — de l'activité arginasique dans la phase prémitotique. Chez des animaux traités par le phénobarbital, l'activité arginasique augmente encore davantage dans la phase prémitotique du foie régénéré.     

The influence of phenobarbital on the glycogen concentration of rat liver

Résumé On a constaté qu'une injection du phénobarbital provoque la diminution de la concentration du glycogène libre de 34% et la diminution du glycogène total de 22,6% seulement 24 h après leur injection. La répétition des injections du phénobarbital diminue le glycogène libre respectivement de 36% et de 28%, le glycogène lié de 46% et de 27%, et le glycogène total de 41% et 24%.     

The effect of Co Q10 on rat liver mitochondria succinoxidase activity in carbon tetrachloride liver injury

Riassunto È stato studiato il comportamento dell'attività succinossidasica dei mitocondri di fegato di ratto normale e intossicato con CCl₄ in presenza di CoQ₁₀. Si è notato che l'aggiunta di CoQ₁₀ in presenza di citocromo c ai mitocondri di fegato grasso stimula la respirazione, fatto che può essere interpretato come aumento di permeabilità della membrana mitocondriale.     

In vivo effect of sodium valproate on mouse liver

The in vivo effect of sodium valproate (SV) on the activity of uridine diphosphate glucuronosyltransferase (UDP-GT) and hepatotoxicity in the mouse liver was studied. Mice were injected intraperitoneally (IP) with SV at doses varying from 50 to 800 mg/kg per day, for six consecutive days (dose-response group) or at a standard dose of 300 mg/g per day for 2-10 days (time-response group), whereas the controls were injected with normal saline. Valproic acid levels had a positive correlation to the dose (P < 0.001) and duration of drug administration (P = 0.006). A gradual increase in UDP-GT activity was observed in doses of up to approximately 400 mg/kg per day, whereas in higher doses the enzyme activity gradually decreased. The time course of UDP-GT activity at the standard dose of 300 mg/kg per day increased progressively, with a maximum up to the sixth day and then had a gradual reduction. Hepatic necrosis (which was unrelated to the dose or the duration of drug administration) was found in 13% of the SV-treated animals and in none of the controls. We conclude that at an optimal dose (300-400 mg/kg per day) and at a time course of 6 days, SV causes liver UDP-GT induction, whereas in higher doses and longer duration of administration, UDP-GT activity is gradually reduced. SV also causes hepatotoxicity unrelated to dose and time course.     

The relationship between the effect of endotoxin on inducible enzymes and biosynthetic activity in rat liver

Résumé Étude du mécanisme d'action de la cortisone. L'induction de tryptophane oxygénase hépatique peut être complètement abolie par l'injection d'endotoxine à un moment où la synthèse hormonale de l'ARN total n'est apparemment pas modifiée.     

Mitogenic activity of selenoorganic compounds in human peripheral blood leukocytes

Summary A variety of organoselenium compounds were originally described as antiinflammatory, antioxidant or glutathione-peroxidase-like agents, and as inhibitors of prostaglandin and leukotriene synthesis. Recently, the compounds have also been found to be inducers of interferon gamma and tumor necrosis factor in human peripheral blood leukocytes (PBL). We evaluated the effects of bis [2-(N-phenylcarboxamido)phenyl] diselenide and Ebselen^®; 2-phenyl-1,2-benzisoselenazol-3(2H)one, on the incorporation of tritiated thymidine into the DNA of PBL cultured in vitro. Both compounds were mitogenic and this effect was correlated with the expression of interleukin 2 receptor in T-lymphocytes. Therefore, we suggest that the selenoorganic compounds may induce mitogenic cytokines.     

Selective effect of noradrenaline on superoxide dismutase activity in the brown adipose tissue and liver of the rat

Summary Noradrenaline treatment results in a significant increase of superoxide dismutase activity in the intrascapular brown adipose tissue but not in the liver.     

Mitogenic activity of selenoorganic compounds in human peripheral blood leukocytes

A variety of organoselenium compounds were originally described as antiinflammatory, antioxidant or glutathione-peroxidase-like agents, and as inhibitors of prostaglandin and leukotriene synthesis. Recently, the compounds have also been found to be inducers of interferon gamma and tumor necrosis factor in human peripheral blood leukocytes (PBL). We evaluated the effects of bis [2-(N-phenylcarboxamido)phenyl] diselenide and Ebselen; 2-phenyl-1,2-benzisoselenazol-3(2H)one, on the incorporation of tritiated thymidine into the DNA of PBL cultured in vitro. Both compounds were mitogenic and this effect was correlated with the expression of interleukin 2 receptor in T-lymphocytes. Therefore, we suggest that the selenoorganic compounds may induce mitogenic cytokines.     

The effect of aging on rat liver regeneration

Summary The effect of age on hepatocyte mensuration and mitotic activity 48 h after partial hepatectomy was investigated in rats. Both age and partial hepatectomy had significant effects upon hepatocyte counts per microscopic field. The number of hepatocytes per microscopic field declined with age in the control groups of different advancing ages and in the experimental groups of advancing ages. There was essentially no mitotic activity in the livers of the control groups. However, mitotic counts were greatly increased in livers from those animals that were partially hepatectomized; the increase in mitotic activity in the 13-month-old animals was double over that observed in both the very young and the very old.Acknowledgment. This research was supported in part by an Eastern Virginia Medical School Biomedical Research Development Fund. The investigators acknowledge the Gerontology Research Center, NIA, Baltimore, Maryland for their support.     

Mitogenic effect of the serum of rats exposed to cold

Summary Serum from rats exposed for 3 days to 5 °C stimulated the multiplication of mouse heteroploid and human and rat diploid cells in culture. The response of the cells to this unspecific growth stimulation was related to the growth capacities of the different cell types.     

The effect of sulfhydryl compounds on the catalytic activity of Cu, Zn-superoxide dismutase purified from rat liver

Sulfhydryl compounds such as reduced glutathione, cysteine and 2-mercaptopropionylglycine, a hepato-protective agent, activated Cu, Zn-superoxide dismutase purified from rat liver at low concentrations (below 10 microM). Furthermore we found evidence indicating that this activation is achieved by reducing Cu2+ present in the catalytic site of the dismutase, and thereby promoting the dismutation of superoxide anions.     

Changes in transglutaminase activity in carbon tetrachloride-damaged rat liver

Summary A significant decrease in transglutaminase (TGase) activity was observed in the cytosol and nuclear fractions of carbon tetrachloride-damaged rat liver. The degree of decrease in TGase activity in the cytosol fraction was closely related to the serum transaminase level. Gel filtration studies revealed that TGase activity in 80 kDa fractions significantly decreased, but that in 160 kDa fractions slightly increased after carbon tetrachloride treatment.     

Corticosteroids and the radiation effect in regenerating liver of the rat

Résumé La vitesse de régénération du foie chez le rat surrénalectomisé, irradié, est comparée à celle du rat normal radioprotégé, afin d'établir si la sécrétion des corticostéroides est en partie responsable de l'inhibition de la mitose provoquée par la radiation.Dans le présent travail, il est démontré que le rat surrénalectomisé possède une vitesse de mitose quatre fois supérieure à celle du rat normal, et ceci malgré d'importants dégâts causés au foie par la radiation.     

Effect of cerium on drug metabolizing activity in rat liver

Zusammenfassung Es wird gezeigt, dass i.v. injiziertes Cerium (2 mg/kg) eine hemmende Wirkung auf den Stoffwechsel von Arzneien in der Rattenleber hat.     

Monoamine oxidase activity in membrane structures of rat liver cell

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Effect of experimental chronic renal failure upon the production of urea,as measured by the liver arginase activity in rats

Summary A significant diminution in liver arginase activity of chronic renal failure uremic rats is described, thus implying that the experimental finding of an increased urea production is not due to a depressed arginase activity.This work was supported by the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico do Brasil's Grants. —Acknowledgments. We are indebted to Mr D'Arrochela Lobo for technical assistance, Mr Celso Chiarin for the statistical review and Dr C.E. Tosta and Dr Linda Caldas for helpful advice.