Bildung von Chloroform aus Tetrachlorkohlenstoff in Lebermikrosomen, Lipidperoxidation und Zerst�rung von Cytochrom P-450

Dietary influence of selenium on the incidence of N‐nitrosodiethylamine‐induced hepatoma with reference to drug and glutathione metabolizing enzymes

“…33 Will 34 has suggested that the system involved in lipid peroxidation (LPO) at least with group 2; b As compared with group 1; c As compared with group 4; d As compared with group 6; e As compared with group 8 (*p < 0.05, @ p < 0.01, # p < 0.001, NS, not statistically significant) selenium against hepatoma with reference to drug and glutathione metabolizing enzymes 353 partially resembles the drug-hydroxylating system, and approximate parallelism was observed between the formation of malondialdehyde and the loss of microsomal enzymes and cytochrome P 450 . 35 The observed decrease in the cytochrome P 450 , cytochrome b 5 , hydroxylating and oxidizing enzymes level (Tables 1 and 2) in hepatoma-bearing rats appears to be either a result of damage to membrane lipids by free radicals or to complex formation between alkylating agents and DNA. 36 In previous studies we have also observed an increased level of LPO in liver of hepatoma-bearing rats.…”

“…This study is in line with other findings that selenium is a well-known antioxidant. GSH-chelating agents 35 and free radical trapping agents. 38 have been reported to preserve cytochrome P 450 by blocking LPO.…”

The apparent loss of cytochrome P-450 associated with metabolic activation of carbon tetrachloride.

“…The in vivo administration and in vitro addition of carbon tetrachloride to the incubation mixture decrease the apparent content of cytochrome P-450 in liver microsomes (1,2). The decrease in the cytochrome P-450 content has been attributed to one or two possibilities.…”

“…One is that cytochrome P-450 heme is degraded by a peroxidative reaction initiated by the trichloromethyl radical, a reactive intermediate formed during the reduction of carbon tetrachloride (2,3). The other is that the trichloromethyl radical binds covalently to cyto chrome P-450 in a chemical manner via reductive dehalogenation (4).…”

Effect of chrysene and carbon tetrachloride administration on rat hepatic microsomal monooxygenase and UDPglucuronosyltransferase activity

“…Means and standard errors of the means are indicated. [27,28]. Attack on membrane lipids by carbon tetrachloride also produces fatty acids which are capable of activating UDPglucuronosyltransferase in vitro [29] .…”