• BMB Reports
• /
• v.33 no.3
• /
• pp.213-220
• /
• 2000

A fulminant hepatitis is associated with massive liver cell necrosis and a high mortality rate. But survivors regenerate a normal liver and do not have chronic liver disease. This clinical course suggests that the acutely injured livers release a factor that allows a recovery from chronic hepatitis or cirrhosis. The objective of this study was to isolate and characterize an anti-fibrotic factor from acutely damaged rat livers. The liver cell necrosis was prepared from rat by warm ischemical perfusion and the perfusates were assessed against the growth inhibition of fat-storing cells (FSC). A liver-derived growth inhibitory factor (LDGIF) was purified from ischemically damaged rat livers by chromatographies on Sephacryl S-300, CM Sepharose, hydroxyapatite, and Superose 12. The LDGIF was isolated with an overall purification of 194-fold and 40% recovery. Although LDGIF was identified as the rat liver arginase by Nterminal sequence analysis, LDGIF exists as a monomer and the purified native arginase has a trimer form. Furthermore, LDGIF has a lower enzyme activity on the hydrolysis of L-arginine and a higher inhibitory effect on proliferation of FSC than the normal rat liver arginase. The catalytic activity of LDGIF is ascribed to the monomeric characteristics of the LDGIF. Therefore, the inhibitory action of LDGIF might not be due to the arginine depletion by the catalytic activity of arginase. In conclusion, the presence of the LDGIF could interpret the clinical course that serious fibrosis is not found in the liver of patients recovering from severe hepatic necrosis due to fulminant hepatitis, suggesting that this LDGIF may provide a novel target for the prevention and treatment of hepatic fibrosis.

• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.5
• /
• pp.591-595
• /
• 1997

An ex vivo assay determining the flavin-containing monooxygenase (FMO) activity in perfused rat liver has been developed by assessing the rate of thiobenzamide S-oxide (TBSO) formation from the infused thiobenzamide (TB). The hepatotoxicity by TB or TBSO was not a critical factor for maintaining the FMO activity for up to 50 min. The FMO activity expressed in nmoles TBSO produced/g liver/min was the same for the recycling and non-recycling perfusion. This implies that reduction of the oxidized TBSO back to the parent compound (TB) is negligible. Hydrolysis of the collected perfusates with either ${\beta}-glucuronidase$ or arylsulfatase did not increase the TBSO level and thus, TBSO does not appear to undergo conjugation either to glucuronide or sulfate esters. Thus, measuring the rate of TB S-oxidation in the isolated perfused liver with 1 mM TB for 50 min provides a useful tool for evaluation of the hepatic FMO activity in the absence of hepatic necrosis and without the interferences caused by further conjugation or back reduction of the TBSO to the parent TB.

• YAKHAK HOEJI
• /
• v.42 no.4
• /
• pp.422-430
• /
• 1998

In order to study the effects of Rhei rhizoma, Ephedrae herba and Scutellariae radix on hepatic metabolism, we examined the pretreatment effect of those on the metabolism of 7-e thoxycoumarin (EC). Water extracts (1g/kg) of Rhei rhizoma, Ephedrae herba and Scutellariae radix were administered orally to rats for 7 days, respectively. Livers were then isolated and perfused with 100mcM EC for 2 hours. The metabolites of EC, 7-hydroxycoumarin, sulfate conjugate and glucuronide conjugate were measured in the perfusates. The amount of glucuronide conjugates was decreased in Rhei rhizoma pretreated rats (p<0.01), however, 7-hydroxycoumarin was increased in Ephedrae herba pretreated rats (p<0.01). We examined whether the change of enzyme activity is related to the change of cytochrome P4501A1 and P4502B1 mRNA level in the perfused rat liver, which are responsible for EC metabolism. CYP1A1 and CYP2B1 mRNA level was increased, which was was not statistically significant with rhei rhizoma nor ephedrae herba pretreatment. We also assessed the hepatotoxicity of Rhei rhizoma, Ephedrae herba and Scutellariae radix. The activities of ALT and AST were assayed at 24 hours after 7 days administration. Only the ratio of ALT over AST was increased in ephedrae herba pretreated rats (p<0.05). Lipid peroxidation was increased in Rhei rhizoma treatment (p<0.05), while histopathological examination performed after liver perfusion did not show any difference compared with vehicle treatment. These results suggest that Ephedrae herba pretreatment increases the o-deethy-lation of 7-ethoxycoumarin in rats, which may be mediated by CYP1A1 mRNA induction.