Impairment of debrisoquine 4-hydroxylase and related monooxygenase activities in the rat following treatment with propranolol.
The effect of repetitive oral administration of propranolol on hepatic microsomal drug metabolizing enzyme activities in the rat was investigated. Propranolol ring (4-, 5- and 7-)hydroxylase activities were markedly decreased, but, interestingly, N-desisopropylase activity was increased after propranolol administration. A marked decrease in enzyme activity after propranolol pretreatment was also observed with debrisoquine 4-hydroxylation. In addition, a similar decrease was observed with imipramine 2-hydroxylation which co-segregates with debrisoquine/sparteine type polymorphic drug oxidation, but not with imipramine N-demethylation. These results suggest the selective impairment of debrisoquine 4-hydroxylase by propranolol pretreatment.
Masubuchi
Y
Y
Department of Biopharmaceutics, Faculty of Pharmaceutical Sciences, Chiba University, Japan.
Fujita
S
S
Chiba
M
M
Kagimoto
N
N
Umeda
S
S
Suzuki
T
T
D000818:Animals; D019389:Cytochrome P-450 CYP2D6; D065607:Cytochrome P-450 Enzyme Inhibitors; D003647:Debrisoquin / Q000378:metabolism; D007099:Imipramine / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors*; D010105:Oxygenases / Q000037:antagonists & inhibitors*; D011433:Propranolol / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D065607:Cytochrome P-450 Enzyme Inhibitors; D011433:Propranolol; D006899:Mixed Function Oxygenases; D010105:Oxygenases; D019389:Cytochrome P-450 CYP2D6; D007099:Imipramine; D003647:Debrisoquin