• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.4
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• pp.573-583
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• 2015

B-32 is one of a panel of monoclonal anti-idiotypic antibodies to growth hormone (GH) that we developed. To characterize and identify its potential role as a novel growth hormone receptor (GHR) agonist, we determined that B-32 behaved as a typical $Ab2{\beta}$ based on a series of enzyme-linked immunosorbent assay assays. The results of fluorescence-activated cell sorting, indirect immunofluorescence and competitive receptor binding assays demonstrated that B-32 specifically binds to the GHR expressed on target cells. Next, we examined the resulting signal transduction pathways triggered by this antibody in primary porcine hepatocytes. We found that B-32 can activate the GHR and Janus kinase (2)/signal transducers and activators of transcription (JAK2/STAT5) signalling pathways. The phosphorylation kinetics of JAK2/STAT5 induced by either GH or B-32 were analysed in dose-response and time course experiments. In addition, B32 could also stimulate porcine hepatocytes to secrete insulin-like growth factors-1. Our work indicates that a monoclonal anti-idiotypic antibody to GH (B-32) can serve as a GHR agonist or GH mimic and has application potential in domestic animal (pig) production.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.96-102
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• 1998

Primary hepatocytes of small animals such as rat and rabbit were often used for the study of extracorporeal liver support systems. Freshly isolated rat hepatocytes form spheroids within tow days when cultivated as suspension in spinner vessels. These spheroids showed enhanced liver specific functions and more differentiated morphology compared to hepatocytes cultured as monolayers However, shear stress caused by continuous agitation deteriorated spheroids gradually. In this work we immobilized spheroids to prolong liver specific activities. First, hepatocyte spheroids were suspended in collagen solution containing calcium chloride and then dropped into alginate solution. A thin layer of calcium alginate was formed around the droplet and then was removed after the inner collagen was gelled by treatment of sodium citrate buffer. Spheroids embedded in collagen-gel bead maintained liver specific functions such as albumin secretion rate longer than hepatocyte spheroids exposed to shear stress. Therefore, we suggest that this immobilization technique may offer an effective long-term hepatocyte cultivation and facilitase the development of a bioartificial liver support device.

• Korean Journal of Pharmacognosy
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• v.22 no.4
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• pp.219-224
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• 1991

Liver protective effects of ginsenosides as well as fractions of dammarane glycosides of Panax ginseng were studied using galactosamine (GalN)-induced cytotoxicity in primary cultured rat hepatocytes. Preventing effects on GalN-induced hepatotoxicity were found both microscopic observation and determination of GPT level with total dammarane glycosides fraction and $20(S)-ginsenoside-Rb_1$ as well as $20(S)-ginsenoside-Rg_1$ at the concentration of $50{\mu}g/ml$. The syntheses of both protein and RNA were significantly increased by the treatment of $50{\mu}g/ml$ of total dammarane glycoside fraction, $20(S)-ginsenoside-Rb_1$, -Rc, -Re and $-Rg_1$, respectively in both normal and GalN-induced cytotoxic hepatocytes.

• Proceedings of the Ginseng society Conference
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• 1998.06a
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• pp.263-269
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• 1998

It is an established fact that most of the carcinogens implicate bay-region diol epoxides as the ultimate carcinogenic metabolites. These electrophiles react with nucleophilic sites in the cells to form abducts. It is the formation of carcinogenic-DNA adducts that is thought to initiate carcinogenesis. In our previous study we have reported chemopreventive property of Ginseng on 7,12-dimethylbenz (a)anthracene (DMBA) induced skin papillomagenesis in male Swiss albino mice. In this study we have examined the effect on formation of DMBA-DNA adducts in rat hepatocytes pretreated with ginseng. Primary cultures of rat hepatocytes were used. The cells wets treated with ginseng for 24 hrs and then with DMBA (iOn) for 18 hrs. Cells were then harvested, their DNA was isolated and analyzed by P)2 labelling. A significant reduction in the levels of DMBA-DNA adduces (adducts/108 nucleotides) was observed in all cultures pretreated with ginseng. The viability of cells was not affected by pre-treatment with ginseng. Our finding suggests that ginseng block or suppresses the events associated with chemical carcinogenesis by inhibiting metabolic activation of the carcinogens.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2004.05a
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• pp.90-90
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• 2004

• 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.

• 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.

• Genomics & Informatics
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• v.8 no.1
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• pp.41-49
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• 2010

Statins are competitive inhibitors of hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase and used most frequently to reduce plasma cholesterol levels and to decrease cardiovascular events. However, statins also have been reported to have undesirable side effects such as myotoxicity and hepatotoxicity associated with their intrinsic efficacy mechanisms. Clinical studies recurrently reported that statin therapy elevated the level of liver enzymes such as ALT and AST in patients suggesting possible liver toxicity due to statins. This observation has been drawn great attention since statins are the most prescribed drugs and statin-therapy was extended to a larger number of high-risk patients. Here we employed rat primary hepatocytes and microarray technique to understand underlying mechanism responsible for statin-induced liver toxicity on cell level. We isolated genes whose expressions were commonly modulated by statin treatments and examined their biological functions. It is of interest that those genes have function related to response to stress in particular immunity and defense in cells. Our study provided the basic information on cellular mechanism of statin-induced cytotoxicity and may serve for finding indicator genes of statin -induced toxicity in rat primary hepatocytes.

• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.315-322
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• 2006

Ethanol abuse is associated with liver injury, neurotoxicity, modulation of immune responses, and increased risk for cancer, whereas moderate ethanol consumption exerts protective effects against liver injury. However, the underlying signal transduction mechanisms of insulin-like growth factors (IGFs) which play an important regulatory role in various metabolism mechanisms are not well understood. We investigated the effects of ethanol-induced p42/44 activity on IGF-I secretion, IGF-I receptor and IGFBP-1 secretion using radioimmunoassay and western blotting in primary cultured rat hepatocytes. The p42/44 activity, IGF-I secretion and IGF-I receptor activity significantly accelerated compared to control at 10 and 30 min after 200 mM ethanol treatment, but then it became suppressed at 180 min. In contrast, IGFBP-1 secretion was inhibited compared to control at 30 min after 200 mM ethanol treatment, but increased at 180 min. The IGF-I secretion, IGF-I receptor and p42/44 activity at 30 min after 200 mM ethanol treatment accelerated with increasing ethanol concentration but IGFBP-1 secretion inhibited (p<0.05). The increased IGF-I secretion, inhibited IGFBP-1 secretion and IGF-IR activity by ethanol-induced temporal p42/44 activity at 30 min after ethanol treatment was blocked by treatment with PD98059. Alcohol dehydrogenase (ADH) inhibitor, 4-methylpyramazole blocked the changes of IGF-I secretion, IGFBP-1 secretion, and IGF-IR activity by ethanol-induced p42/44 activity at 30 and 180 min. Taken together, these results suggest that ethanol is involved in the modulation of IGF-I and IGFBP-1 secretion and IGF-IR activity by p42/44 activity in primary cultured rat hepatocytes. In addition, changing of p42/44 activity by ethanol was caused with ADH.