• Proceedings of the PSK Conference
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• 2003.04a
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• pp.212.2-212.2
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• 2003

Primary cultured rat hepatocytes injured by carbon tetrachloride as a model to screen for hepatoprotective effect. Four flavonoid compounds showed anti-hepatotoxic effect by decrease GPT. LDH activity and MDA level. Also screen for hepatoprotective, anti-oxidative and anti-apoptosis effects of baicalin and baicalein on chang cell treated with t-BHP. Mesured radical detoxifying enzyme, GST and antioxidant enzyme SOD, Catalase activity, GSH level and Cellular glutathion peroxidase activity. (omitted)

• Environmental Analysis Health and Toxicology
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• v.22 no.3
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• pp.227-233
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• 2007

It has been reported that hepatic glutathione (GSH) levels are decreased in diabetic patients, and glucagon increases hepatic efflux of GSH into blood. The signaling pathways responsible for mediating the glucagon effects on GSH efflux, however, are unknown. The signaling pathways involved in the regulation of GSH efflux in response to glucagon and insulin were examined in primary cultured rat hepatocytes. The GSH concentrations in the culture medium were markedly increased by the addition of glucagon, although cellular GSH levels are significantly decreased by glucagon. Insulin was also increased the GSH concentrations in the culture medium, but which is reflected in elevations of both cellular GSH and protein. Treatment of cells with 8-bromo-cAMP or dibutyryl-cAMP also resulted in elevation of the GSH concentrations in the culture medium. Pretreatment with H89, a selective inhibitor of protein kinase A, before glucagon addition markedly attenuated the glucagon effect. These results suggest that glucagon changes GSH homeostasis via elevation of GSH efflux, which may be responsible for decrease in hepatic GSH levels observed in diabetic condition. Furthermore, the present study implicates cAMP and protein kinase A in mediating the effect of glucagon on GSH efflux in primary cultured rat hepatocytes.

• Toxicological Research
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• v.23 no.4
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• pp.301-309
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• 2007

Paecilomyces tenuipes (PT), one of the Ascomycetes family, has been used for medicinal purposes due to its broad pharmacological activities. The present study was undertaken to investigate the hepatoprotective effects of PT water extracts against $CCl_4$-induced hepatotoxicity in primary cultures of adult rat hepatocytes. When the extract of PT was directly added into the culture medium at 1, 2, and 5 mg/ml, the extracts not only reduce the $CCl_4$-induced elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase, and lipid peroxide, but also protect cultured hepatocytes from $CCl_4$-induced reduction of reduced glutathione, glutathione reductase, glutathione-S-transferase, glutathione peroxidase, catalase and superoxide dismutase. In addition, the effects of PT water extracts on cytochrome P450 enzymes were relatively marginal, indicating that the hepatoprotective effects of PT extract against $CCl_4$-induced toxicity might not be due to the inhibition of $CCl_4$ activation. In conclusion, the PT extracts were effective in protecting against $CCl_4$ induced hepatotoxicity in hepatocyte cultures, at least in part, by scavenging free radicals, and by modulating enzyme systems involved in cellular oxidative stress.

• Environmental Analysis Health and Toxicology
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• v.21 no.3 s.54
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• pp.245-253
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• 2006

We reported previously that glucagon decreased alpha- and pi-class glutathione S-transferases (GSTs) and microsomal epoxide hydrolase (mEN) protein levels in primary cultured rat hepatocytes. The present study examines the effects of Protein kinase A (PKA) inhibitor, KT5720, on the glucagon-mediated decrease in expression of GSTs and mEN. To assess cell viability. lactate dehydrogenase release and MTT activity were examined in hepatocytes treated KT5720. Cell viability was significantly decreased in a concentration dependent manner after incubation with KT5720 at the concentrations of 1 $\mu$M or above for 24 h, which was inhibited by the cytochrome P450 inhibitor SKF-525A. In contrast, another PKA inhibitor H89 (up to 25 $\mu$M) was not toxic to hepatocytes. The glucagon-mediated decrease in expression of alpha- and pi-class GSTs and mEH was completely inhibited by 25 $\mu$M H89 and attenuated by 0.1 $\mu$M KT5720. This study demonstrates that KT5720 may cause cytotoxicity in rat hepatocytes through cytochrome P450-dependent bioactivation. The present study implicates PKA in mediating the inhibitory effect of glucagon on expression of alpha- and pi- class GSTs and mEH.

• Toxicological Research
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• v.14 no.4
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• pp.507-513
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• 1998

The purpose of this study was to clarify the effect of silica on cytosolic free calcium mobilization and cell injury in primary cultured rat hepatocytes. Cytosolic free calcium concentration ([Ca$^{2+}$]) was measured employing calcium sensitive fluorescent dye, Fura-2 / AM, and cell injury was evaluated by determination of cellular ATP contents. Silica increased [Ca$^{2+}$], in a concentration-dependent manner in hepatocytes (10$^{-5}$ ~10$^{-2}$ M). Silica caused a biphasic increase in [Ca$^{2+}$], which was composed of an initial rapid rise and following sustained phase. $Ca^{2+}$ removal from the medium resulted in abolishment of initial and sustained phase of silica (10$^{-2}$ M)-induced [Ca$^{2+}$], in hepatocytes. The pretreatment with nifedipine (1 $\mu$M) attenuated silica-induced [Ca$^{2+}$], increases. Silica decreased cellular ATP contents in a dose-dependent manner. This silica-induced cell injury was attenuated by the pretreatment with EGTA (100 $\mu$M) and nifedipine (1 $\mu$M). This study suggests that the elevation of [Ca$^{2+}$], caused by silica may be due mainly to influx through a plasma membrane $Ca^{2+}$ channel and hepatotoxicity by silica relate with alteration of calcium homeostasis.ium homeostasis.

• YAKHAK HOEJI
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• v.50 no.6
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• pp.358-366
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• 2006

The aim of this study was to investigate the protective effects of glycynhizin, active glycosides of Glycyrrhizae Radix, and baicalin, bioactive flavonoid isolated from Scutellariae Radix, on hepatocyte injury induced by carbon tetrachloride(CCl$_4$, 10 mM), tert-butyl hydroperoxide (TBH, 0.5 mM), and D-galactosamine (GaIN, 30 mM). Primary cultures of rat hepatocyte (18 hr cultured) were treated with CCl$_4$, TBH, or GaIN and various concentrations (0.1, 1, 10, and 100 ${\mu}$M) of glycyrrhizin or baicalin. Activity was accessed by determining the release of lactate dehydrogenase (LDH) and aminotransferses. CCl$_4$ significantly increased the levels of LDH, alanine aminotransferase (ALT), and aspartate aminotransferase(AST) and these increases were prevented by baicalin concentrations of 0.1,1, and 100 ${\mu}$M. The increases in ALT and AST levels were reduced by glycyrrhizin concentration of 100 ${\mu}$M. The level of LDH was markedly increased by TBH, and this increase was reduced by both glycyrrhizin and baicalin. ALT and AST levels were increased by TBH, which were prevented by glycynhizin and bacalin, respectively: GaIN markedly increased the levels of LDH, ALT and AST These increases was significantly reduced by both glycyrrhizin and baicalin. These results suggest that glycynhizin and baicalin possess the hepatoprotective activity.

• Korean Journal of Pharmacognosy
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• v.22 no.2
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• pp.95-100
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• 1991

Salviae miltiorrhizae(SM) Radix extract increased $[^3H]-thymidine$ incorporation into rat hepatocytes at the concentration ranging from $5{\times}10^{-5}\;to\;5{\times}10^{-1}mg/ml$. It decreased the activities of s-GOT and s-GPT in cirrhotic rats induced by $CCl_4$, TAA and D-GalN, respectively and reduced the sleeping time induced by hexobarbital in $CCl_4$,TAA and D-GalN intoxicated mice, respectively. SM extract shortened the half-life of sulfobromophthalein in $CCl_4$ intoxicated rats.

• Korean Journal of Pharmacognosy
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• v.27 no.2
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• pp.111-116
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• 1996

The components were isolated from the root of Astragalus membranaceus and their structures were characterized as 3,4-methylenedioxypyrrolealdehyde, $7-O-{\beta}-D-glucopyranosyl$ 7, 3'-dihydroxy-4'-methoxy isoflavone and a naphthalene derivative on the basis of spectral and physical methods. $7-O-{\beta}-D-glucopyranosyl$ 7, 3'-dihydroxy-4'-methoxy isoflavone and the naphthalene compound showed protective effect on $CC_{l4}-induced$ cytotoxicity in primary cultured rat hepatocytes.

• Proceedings of the Korean Society of Toxicology Conference
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• 2005.05a
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• pp.112-112
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• 2005

• Archives of Pharmacal Research
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• v.13 no.4
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• pp.355-358
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• 1990

In order to investigate the cellular mechanisms of hypoglycemic of brazilin, hepatocyte monolayer culture was introduced and, glycogen synthesis rate and insulin binding were measured as parameters. Glycogen synthesis and insulin sensitivity were remarkably augmented by the treatment of brazilin. Brazilin slightely increased insulin binding. Scatchard analysis revealed that this increase in insulin binding was not due to increase in the binding capacity but in binding affinity. These results suggest that the augmentation of hepatic glycogenesis and insulin sensitivity by brazilin may play an important role in the improvement of hyperglycemia.