title: Effects of dithiocarb and (+)-catechin on microsomal enzyme activities of rat liver.
abstract: The effects of dithiocarb and (+)-catechin on the microsomal mixed-function oxidase system of rat liver were investigated after a single dose as well as after repeated treatment for 7 and for 28 days. Dithiocarb (200 mg/kg p.o.) significantly reduced the microsomal cytochrome P-450 content, aniline hydroxylase and aminopyrine demethylase activities; maximum decrease was observed at 4 hrs, return to normal values after 24 hrs. (+)-catechin (200 mg/kg p.o.) had no effects in this respect. Both agents did not affect microsomal enzyme activities when applied orally for 7 days. After 28 days treatment only dithiocarb (50 - 100 - 200 mg/kg p.o.) exerted a dose-dependent depression of the aniline hydroxylase activity. In vitro experiments confirmed the in vivo observations: a concentration-dependent inhibition of the aniline hydroxylation and aminopyrine demethylation were seen from the addition of dithiocarb, the I50-values were 5.4 X 10(-6) M and 9.6 X 10(-5) M, respectively. (+)-catechin showed no inhibitory activity on both enzyme activities in vitro. Both dithiocarb and (+)-catechin depressed the activity of the NADPH-cytochrome C-reductase only in the 10(-4) M concentration range, these effects should be therefore evaluated as non-physiological without relevance in vivo.
mesh_terms: D000818:Animals; D001578:Benzopyrans / Q000494:pharmacology*; D002392:Catechin / Q000494:pharmacology*; D004050:Ditiocarb / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013859:Thiocarbamates / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D001578:Benzopyrans; D013859:Thiocarbamates; D002392:Catechin; D004050:Ditiocarb; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases