Hepatocytes carbon tetrachloride

The relative importance of hepatic microsomal lipid peroxidation versus covalent binding of carbon tetrachloride-derived radicals has been the subject of considerable debate. Since cytochrome P-450 loss has been shown to be related to lipid peroxidation and to covalent binding, each in the absence of the other, both of these early consequences of carbon tetrachloride metabolism may contribute to P-450 destruction. Nevertheless, it is still not clear how these initial events are related to subsequent triglyceride accumulation, polyribosomal disaggregation, depression of protein synthesis, cell membrane breakdown and eventual death of the hepatocytes. Carbon tetrachloride... 

Acute Liver Damage Several compounds (e.g., dimethyl iiitrosoamine, carbon tetrachloride, and thioacetamide) cause necrosis of hepatocytes by inhibiting pro tein syndiesis at the translational level, i.e., by inhibiting the addition of new amino adds into the protein chain being sjTithetized. This is not, however, the only mechanism. Ethioiiine is a compound which inhibits protein synthesis bur doe not induce... 

The identification and quantification of potentially cytotoxic carbonyl compounds (e.g. aldehydes such as pentanal, hexanal, traw-2-octenal and 4-hydroxy-/mAW-2-nonenal, and ketones such as propan- and hexan-2-ones) also serves as a useful marker of the oxidative deterioration of PUFAs in isolated biological samples and chemical model systems. One method developed utilizes HPLC coupled with spectrophotometric detection and involves precolumn derivatization of peroxidized PUFA-derived aldehydes and alternative carbonyl compounds with 2,4-DNPH followed by separation of the resulting chromophoric 2,4-dinitrophenylhydrazones on a reversed-phase column and spectrophotometric detection at a wavelength of378 nm. This method has a relatively high level of sensitivity, and has been successfully applied to the analysis of such products in rat hepatocytes and rat liver microsomal suspensions stimulated with carbon tetrachloride or ADP-iron complexes (Poli etui., 1985). 

Poli, G., Dianzani, M.U., Cheeseman, K.H., Slater, T.F., Lang, J. and Esterbauer, H. (1985). Separation and characterization of the aldehydic products of lipid peroxidation stimulated by carbon tetrachloride or ADP-iron in isolated rat hepatocytes and rat liver microsomal suspensions. Biochem. J. 227, 629-638,... 

Biasi, F., Albano, E., Chiarpotto, E., Corongju, F.P., Pron-zato, M.A., Marinari, U. M., Parola, M., Dianzani, M.U. and Poli, G. (1991). Invivo and in vitro evidence concerning the role of lipid peroxidation in the mechanism of hepatocyte death due to carbon tetrachloride. Cell Biochem. Function 9, 111-118. 

Glende, E.A. and Pushpendian, C.K. (1986). Activation of phospholipase A2 by carbon tetrachloride in isolated rat hepatocytes. Biochem. Pharmacol. 35, 89-96. 

Glende EA Jr, Lee PY. 1985. Isopropanol and chlordecone potentiation of carbon tetrachloride liver injury Retention of potentiating action in hepatocyte suspensions prepared from rats given isopropanol or chlordecone. Exp Mol Pathol 42(2) 167-174... 

Mehendale HM, Ray SD, Cai Z. 1991. Paradoxical toxicity of carbon tetrachloride in isolated hepatocytes from chlordecone, phenobarbital and mirex pretreated rats. In Vitro Toxicology 4(3) 187-196. 

Bai CL, Stacey NH. 1993. Effects of carbon tetrachloride and chloroform on bile acid transport in isolated rat hepatocytes relationship to elevated serum bile acids. Toxic In Vitro 7(3) 197-203. 

Ruch RJ, Klaunig JE, Schultz NE, et al. 1986. Mechanisms of chloroform and carbon tetrachloride toxicity in primary cultured mouse hepatocytes. Environ Health Perspect 69 301-305. 

The mechanism of carbon tetrachloride hepatotoxicity generally is viewed as an example of lethal cleavage, where the CCh— Cl bond is split in the mixed-function oxidase system of the hepatocytes. After this cleavage damage may occur directly from the free radicals (-CCl and -Cl) and/or from the formation of toxic metabolites such as phosgene." ... 

Oral exposure of rats to a single dose of 100 mg/kg carbon tetrachloride did not result in unscheduled DNA synthesis in hepatocytes isolated from the treated animals (Mirsalis and Butterworth 1980). The effect of other dose levels or repeated exposures was not investigated. In a similar experiment, Craddock and Henderson (1978) found that oral exposure of rats to carbon tetrachloride caused an increase in DNA synthesis associated with tissue regeneration, but no increase in unscheduled DNA synthesis. Furthermore, chromosome aberrations, micronuclei, or sister chromatid exchanges were not induced within 4-72 hours in hepatocytes take from rats treated with the relatively high dose of 1,600 mg/kg (Sawada et al. 1991). 

Immunological Effects. The effects of carbon tetrachloride on the immune system have not been evaluated in humans. Immune responses were not affected in rats orally exposed to carbon tetrachloride (Smialowicz et al. 1991). Parenteral exposure of animals to carbon tetrachloride has been reported to impair the immune system (Kaminski et al. 1989 Muro et al. 1990 Tajima et al. 1985), and oral exposure caused depletion of lymphocytes, hemorrhage, and hemosiderin deposition in the pancreaticoduodenal lymph node (Doi et al. 1991). These findings are supported by in vitro studies in which the IgM antibody formation response of isolated mouse splenocytes to sheep erythrocytes was inhibited in a dose-dependent manner when the splenocytes were exposed to carbon tetrachloride for 1-3 hours in the presence of cocultured hepatocytes (Kaminski and Stevens 1992). No effects were observed in the absence of cocultured hepatocytes. Mice appear to be more sensitive than rats to carbon tetrachloride-induced immunosuppression, but the biological significance to humans of these reported effects are yet ascertainable from the available data. 

Comparative Toxicokinetics. Metabolic pathways and mechanisms of hepatotoxicity of carbon tetrachloride have been the subject of many studies in intact animals and in vitro, and are therefore better understood than for many other chemicals. However, there are apparently no data on metabolism of carbon tetrachloride in humans. It would be valuable to conduct in vitro experiments with human liver samples and hepatocytes to determine whether metabolic pathways and toxic metabolites are similar to those found in animals. It would also be beneficial to identify an animal model in which MFO systems develop in uteroas they do in the human fetus. 

Basis for differences in carbon tetrachloride effects on periportal and pericentral hepatocytes enzymic and metabolic variations. 

Andrabi K, Kaul N, Gangly NK, et al. 1989. Altered calcium homeostatis in carbon tetrachloride exposed rat hepatocytes. Biochem International 18 1287- 1295. 

Biasi F, Albano E, Chiarpotto E, et al. 1991. In vivo and in vitro evidence concerning the role of lipid peroxidation in the mechanism of hepatocyte death due to carbon tetrachloride. Cell Biochem Func 9 111-118. 

De Castro CR, Bernacchi AS, De Ferreyra EC, et al. 1978. Carbon tetrachloride induced ultrastructural alterations in pancreatic acinar cells and in the hepatocytes. Similarities and differences. Toxicology 11 289- 296. 

Dogterom P, Nagelkerke JF, van Steveninick J, et al. 1988. Inhibition of lipid peroxidation by disulfiram and diethydithiocarbamate does not prevent hepatotoxin-induced cell death in isolated rat hepatocytes. A study with allyl alcohol, tert-butyl hydroperoxide, diethyl maleate, bromoisovalerylurea and carbon tetrachloride. Chem Biol Interact 66 251-265. 

Glende EA, Recknagel RO. 1992. Phospholipase A2 activation and cell injury in isolated rat hepatocytes exposed to bromotrichloromethane, chloroform, and 1,1-dichloroethylene as compared to effects of carbon tetrachloride. Toxicol AppI Pharmacol 113 159-162. 

Kanta J, Kvasnickova E, Bartos F. 1992. Prolonged reduction of hepatocyte proliferative ability in rats after a single treatment with carbon tetrachloride. Int J Exp Path 73 21-26. 

Kate H, Nakazawa Y. 1987. The effect of carbon tetrachloride on the enzymatic hydrolysis of cellular triacylglycerol in adult rat hepatocytes in primary monolayer culture. Biochem Pharmacol 36 1807-1814. 

Kefalas v, Stacey NFI. 1989. Potentation of carbon tetrachloride-induced lipid peroxidation by trichloroethylene in isolated rat hepatocytes no role in enhanced toxicity. Toxicol AppI Pharmacol 101 158-169. 

Kefalas V, Stacey NFI. 1991. Potentiating effects of chlorianted hydrocarbons on carbon tetrachloride toxicity in isolated rat hepatocytes and plasma membranes. Toxicol AppI Pharmaol 109 171-179. 

Lamb RG, Borzelleca JF, Condie LW, et al. 1989. Toxic interactions between carbon tetrachloride and chloroform in cultured rat hepatocytes. Toxicol AppI Pharmacol 101 106-113. 

Lindroos PM, Zarnegar R, Michalopoulos GK. 1990. Hepatocyte growth factor (hepatopoietin A) rapidly increases in plasma before DMA synthesis and liver regeneration stimulated by partial hepatectomy and carbon tetrachloride administration. Hepatology 13 743-750. 

Long RM, Moore L. 1986a. Elevated cytosolic calcium in rat hepatocytes exposed to carbon tetrachloride. J Pharmacol Exp Ther 238 186-191. 

Long RM, Moore L. 1987. Cytosolic calcium after carbon tetrachloride, 1,1- dichloroethylene, and phenylephrine exposure. Studies in rat hepatocytes with phosphorylase and quin2. Biochem Pharmacol 36 1215-1221. 

Long RM, Moore L. 1988. Biochemical evaluation of rat hepatocyte primary cultures as a model for carbon tetrachloride in rats based on arterial blood inhaled air concentration ratios. Toxicol AppI Pharmacol 92 295-306. 

Pronzato MA, Domenicotti C, Biasi F, et al. 1990. Inactivation of hepatocyte protein kinase C by carbon tetrachloride involvement of drug s metabolic activation and prooxidant effect. Biochem Biophys Res Commun 171 1353-1360. 

Ray P, Moore L. 1986. Carbon tetrachloride-induced release of calcium from isolated hepatocytes. Toxicology 41 205-212. 

Saez JC, Bennett VL, Spray DC. 1987. Carbon tetrachloride at hapatotoxic levels blocks reversibly gap junctions between rat hepatocytes. Science 236 967- 969. 

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