• Archives of Pharmacal Research
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• v.26 no.1
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• pp.64-69
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• 2003

To analyze vasopressin-induced $Ca^{2+}$ increase in liver cells, rat hepatocytes were isolated and attached to collagen-coated cover slips. Using fura-2, a $Ca^{2+}$-sensing dye, changes in intracellular $Ca^{2+}$ concentration by vasopressin were monitored. Results in this communication suggested that vasopressin-induced $Ca^{2+}$ increase were composed of both $Ca^{2+}$ release from internal $Ca^{2+}$ stores and influx from the plasma membrane. The $Ca^{2+}$ influx consisted of two distinguishable components. One was dependent on the presence of vasopressin and the other was not. SK＆F96365 blocked vasopressin-induced $Ca^{2+}$ influx in a dose-dependent manner. Vasopressin-induced $Ca^{2+}$ release from internal stores diminished in a primary culture of hepatocytes according to the culture time. However, changes in vasopressin-induced $Ca^{2+}$ influx across the plasma membrane differed from changes in the $Ca^{2+}$ release from internal stores, suggesting two separate signalings from receptor activation to internal stores and to the plasma membrane.

• The Korean Journal of Pharmacology
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• v.32 no.3
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• pp.399-406
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• 1996

Thioacetamide is a non-genotoxic carcinogen, a protein modifying agent. It causes nucleolar hypertrophy in short term treatment. In the present work, thioacetamide treated hepatocytes were observed in vivo and in vitro conditions. After 7 day treatment of rat liver with thioacetamide, the hepatocyte nucleoli were enlarged and their signalling molecules such as B23 and p38 MAPK were increased. When these hepatocytes were released by collagenases and were grown under the conditions of gene therapy grade tissue culture system, the enlarged nucleoli were further enlarged. The B23 content was again increased under in vitro conditions. From these experiments, it is clear that the hepatocytes possess approximately 100 fold flexibility of nucleolar capacity. It is suggested that thioacetamide enhances the ribosome genesis and exaggerates the nucleologenesis ability.

• Toxicological Research
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• v.3 no.1
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• pp.1-8
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• 1987

In vitro induction of cytochrome 450 associated monooxygenase activities by phenobarbital (PB) and 3-methylcholanthrene (MC) was investigated in primary cultures of adult rat hepatocytes. PB and MC were added to the culture 24 hr after the initial plating of hepatocytes. A signiftcant increase of the activities of 7-ethoxycoumarin 0-deethylase and aryl hydrocarbon hydroxylase were observed in MC and PB treated culture. MC caused about 500% induction of the initial oxidation rates of both enzymes in 48 hr. However the PB maintained both enzyme activities close to the level of freshly isolated hepatocytes. Biphenyl 4-hydroxylase and aminopyrine N-demethylase activities were also induced by MC and PB. But the level of induction was less than that occuring with 7-ethoxycoumarin 0-deethylase and aryl hydrocarbon hydroxylase. When aflatoxin $B_1$ was added to the hepatocyte cultures which have been treated with MC or PB, it caused a significant increase of the unscheduled DNA synthesis at higher dose of aflatoxin $B_1$ as compared to those of untreated control hepatocyte cultures. The results suggest that microsomal enzyme activities can be selectively controlled preferably in hepatocyte cultures by the in vitro induction method. This principle may be useful for studying the metabolism and other toxicological studies.

• Journal of Ginseng Research
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• v.19 no.2
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• pp.108-113
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• 1995

Effect of ginseng polysaccharide fraction was examined for $CCl_4$-induced hepatotoxicity in vitro and in vivo. In $CCl_4$-injured primary cultured rat hepatocytes, treatment of the polysaccharide fraction (0.1, 0.3, 1.0 mg/ml) significantly Inhibited the release of LDH and GOT into the culture medium in a dose-dependent manner. Oral administration of the polysaccharide fraction (100, 200 mg/kg) inhibited the decrease of body weight and the increase of the ratio of liver to body weight in $CCl_4$-intoxicated rats. Elevation of GOT, GPT and ALP activity in the serum by $CCl_4$-induced hepatotoxicity was suppressed by administration of ginseng polysaccharide fraction. MDA levels increased in the serum as well as in the liver tissue by treatment with $CCl_4$ showed a tendency to be 연w in the rats given to the polysaccharide fraction. These results suggest that the polysaccharide fraction may be active substance responsible for antihepatotoxic effect of Panax ginseng.

• Environmental Mutagens and Carcinogens
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• v.7 no.2
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• pp.59-64
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• 1987

Cytotoxic and genotoxic potential of monosodium glutamate (MSG) were evaluated in primary cultures of rat hepatocytes. When exposed to liver cell culture continuously for 24 hr, MSG did not show any cytotoxic effects up to 0.5% (w/v) level as determined by Tryphan Blue exclusion and lactic dehydrogenase release test. MSG also did not induce unscheduled DNA synthesis or DNA single-strand breaks in hepatocyte cultures up to 1% level. No synergistic effects of MSG were observed on aflatoxin B$_1$-induced DNA damage when 1% MSG was treated to liver cell culture along with aflatoxin B$_1$.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.264-268
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• 2001

Aggregates of specific cells are often regarded as better from in artificial organs and mammalian cell bioreactors in terms of cell-specific functionality. In this study, the morphology and liver specific functions of freshly harvested primary rat hepatocytes, which were cultivated as spheroids and entrapped in a synthetic thermo-reversible extracellular matrix, were examined and compared to a control (hepatocytes in single cell form). A copolymer of N-isopropylacrylamide(98 mole % in feed) and acrylic acid (poly (NiPAAm-co-AAC)), a thermo- reversible copolymer gel ma- trix, was used to entrap hepatocytes either in spheroids or single cells. During a 7-day culture pe-riod, the spheroids maintained higher viability and produced albumin and urea at a relatively con-stant rate, while, the single cell culture showed a slight increase in cell numbers and a reduction in albumin secretion Hepatocytes cultrured as spheroids present a potentially useful three-dimensional cell culture system for application in bioartificial liver device.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.6
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• pp.1448-1452
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• 2003

The water extract of Scutellariae radix was treated to rat and the primary culture of hepatocytes, and the expressions of several glutathione S-transferase (GST) isozymes and the activity of GST Yc1/2 were investigated by Western blot and by the use of HPLC. The results were obtained as follows: The water extract of Scutellariae radix did not induce the expressions of cytosolic GST Ya and GST Yp in rat livers. But, the extract increased the expression of cytosolic GST Yc1/2 to 2-4 fold higher than control. The expression of GST Yc1/2 in the primary culture of rat hepatocytes was induced by the water extract of Scutellariae radix in a dose-dependent manner, reaching 21-fold over control with 50 ㎍/㎖ treatment. The induction of the expression of GST Yc1/2 in rat livers increased the formation of AFB₁-glutathione conjugate from AFB₁-8,9-epoxide which was made in the metabolism of AFB₁.

• 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.7 no.2
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• pp.239-255
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• 1991

Several types of IFNs were tested for their ability to suppress TCDD-inducible P-450 dependent mixed function oxidase (MFO) system in mouse primary hepatocytes. Mouse IFN-gamma (IFN-G) markedly suppressed EROD activity when added at the same time as TCDD (10 nM). The antagonism of EROD activity by IFN-G exhibited both a dose-(10-100 U/ml) and time-depedence. In contrast, mouse IFN-A/B was only moderately suppressive and only at high concentrations (500 U/ml). Rat IFN-G was even more selective than mouse, wherase human IFN-G had no activity.

• Korean Journal of Environmental Agriculture
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• v.22 no.2
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• pp.94-99
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• 2003

The objective of present study was to investigate the antioxidative and hepatoprotective effects of selenium on cadmium-induced toxicity and lipid peroxidation in rat hepatocyte primary culture. To do this, two separate experiments were conducted. In Experiment 1, primary cultures of rat hepatocytes were incubated for 6 hr in the presence of various concentrations (1, 10, 50, 100, and $500\;{\mu}M$) of cadmium chloride. Cytotoxicity and lipid peroxidation were evaluated using the MTT assay and TBARS assay, respectively. Antioxidative and hepatoprotective effects were determined by measuring the activity of GOT and GSH-Px, respectively. Cell viability was reduced and lipid peroxidation was increased by cadmium in dose-dependent manners. There was significantly negative correlation (r=-0.943, p<0.01) between cell viability and lipid peroxidation GOT activity was increased and GSH-Px activity was decreased by cadmium at the concentration of $50\;{\mu}M$. In Experiment 2, primary cultures of rat hepatocytes were incubated for 6hr in the presence of 100\;{\mu}M$ of cadmium chloride and various concentrations (0.01, 0.1 and 1 ppm) of sodium selenite to assess the effect of selenium on cadmium-induced toxicity and lipid peroxidation. Cell viability and GSH-Px activity were increased by sodium selenite at the concentration of 1 ppm Whereas, lipid peroxidation and GOT activity were reduced by 0.1 ppm of sodium selenite. These results demonstrate that selenium has an antioxidative and hepatoprotective potentials against cadmium.