Effect of caffeine on the hepatic microsomal mixed function oxidase system during phenobarbital and benzo[a]pyrene treatment in rats.
Simultaneous administration of caffeine (100 mg/kg, i.p., 3 days) and phenobarbital (80 mg/kg, i.p., 3 days) to adult male rats resulted in a significant decrease in hepatic cytochrome P-450 and acetanilide hydroxylase activity, compared to phenobarbital administration alone. While simultaneous administration of caffeine and benzo[a]pyrene (20 mg/kg, i.p., 2 days) increased acetanilide hydroxylase, compared to benzo[a]pyrene administration, no change was seen in the cytochrome P-450 concentration. In vitro addition of 2.5 mM caffeine to microsomal incubations from untreated, phenobarbital- and benzo[a]pyrene-treated rats inhibited aminopyrine N-demethylase activity. No significant difference was seen in the extent of aminopyrine N-demethylase inhibition due to the in vitro addition of caffeine to microsomes from untreated or phenobarbital-treated rats, whereas inhibition in microsomes from benzo[a]pyrene-treated rats was greater.
Govindwar
S P
SP
Department of Chemistry, Marathwada University, Aurangabad, India.
Kachole
M S
MS
Pawar
S S
SS
D000633:Aminopyrine N-Demethylase / Q000378:metabolism; D000818:Animals; D001564:Benzo(a)pyrene / Q000494:pharmacology*; D002110:Caffeine / Q000494:pharmacology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D001564:Benzo(a)pyrene; D002110:Caffeine; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D000633:Aminopyrine N-Demethylase; D010634:Phenobarbital