Selective deficiency of debrisoquine 4-hydroxylase activity in mouse liver microsomes

Yasuhiro Masubuchi, Takashi Iwasa, Shin Hosokawa, Tokuji Suzuki, Toshiharu Horie, Susumu Imaoka, Yoshihiko Funae, Shizuo Narimatsu

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Cytochrome P450 enzymes belonging to the CYP2D subfamily have been shown to be one of determinants of the polymorphic drug oxidations in the human and the rat. Debrisoquine 4-hydroxylation is a typical reaction catalyzed by these enzymes. However, various strains of mice were observed to have much lower debrisoquine 4-hydroxylase activity than Wistar rats, whereas other monooxygenase activities in mice toward bunitrolol, propranolol, imipramine and amitriptyline, which are mediated by the CYP2D enzymes in the rat, were comparable to those of the rats. Immunoblot analysis of mouse liver microsomes with an antibody raised against a rat CYP2D enzyme indicated that the mouse liver contained a P450 enzyme(s) immunochemically related to the rat CYP2D enzyme. The antibody inhibited propranolol ring-hydroxylase and imipramine 2-hydroxylase activities, as well as testosterone 16α-hydroxylase activity, a typical reaction of mouse CYP2D9, but not debrisoquine 4- hydroxylase activity in mouse liver microsomes. We partially purified a P450 enzyme (designated P450 ML2d) from livers of male ddY mice by monitoring the cross-reactivity with the antibody. The partially purified enzyme was indicated to belong to the CYP2D subfamily from its N-terminal amino acid sequence, but the homology of the sequence to other CYP2D enzymes of the mouse (CYP2D9-11) was 62%, suggesting that P450 ML2d is a novel. P450 enzyme. P450 ML2d had the oxidation activities for the rat CYP2D-substrates, such as propranolol 4-hydroxylation and imipramine 2-hydroxylation, in higher rates than those of the microsomes, but did not exhibit debrisoquine 4-hydroxylase activity. Our result is the first finding that a mouse CYP2D enzyme also metabolizes substrates for the rat CYP2D enzyme, in addition to steroids, but the enzyme had a limited specificity for the substrates of the CYP2D enzymes of the rat and the human.

Original languageEnglish
Pages (from-to)1435-1441
Number of pages7
JournalJournal of Pharmacology and Experimental Therapeutics
Volume282
Issue number3
Publication statusPublished - Sep 1997
Externally publishedYes

Fingerprint

Cytochrome P-450 CYP2D6
Liver Microsomes
Enzymes
Cytochrome P-450 Enzyme System
Hydroxylation
Mixed Function Oxygenases
Propranolol
Imipramine
Antibodies
Debrisoquin
Amino Acid Sequence Homology
Amitriptyline
Liver
Substrate Specificity
Microsomes
Testosterone
Wistar Rats
Steroids

ASJC Scopus subject areas

  • Pharmacology

Cite this

Masubuchi, Y., Iwasa, T., Hosokawa, S., Suzuki, T., Horie, T., Imaoka, S., ... Narimatsu, S. (1997). Selective deficiency of debrisoquine 4-hydroxylase activity in mouse liver microsomes. Journal of Pharmacology and Experimental Therapeutics, 282(3), 1435-1441.

Selective deficiency of debrisoquine 4-hydroxylase activity in mouse liver microsomes. / Masubuchi, Yasuhiro; Iwasa, Takashi; Hosokawa, Shin; Suzuki, Tokuji; Horie, Toshiharu; Imaoka, Susumu; Funae, Yoshihiko; Narimatsu, Shizuo.

In: Journal of Pharmacology and Experimental Therapeutics, Vol. 282, No. 3, 09.1997, p. 1435-1441.

Research output: Contribution to journalArticle

Masubuchi, Y, Iwasa, T, Hosokawa, S, Suzuki, T, Horie, T, Imaoka, S, Funae, Y & Narimatsu, S 1997, 'Selective deficiency of debrisoquine 4-hydroxylase activity in mouse liver microsomes', Journal of Pharmacology and Experimental Therapeutics, vol. 282, no. 3, pp. 1435-1441.
Masubuchi Y, Iwasa T, Hosokawa S, Suzuki T, Horie T, Imaoka S et al. Selective deficiency of debrisoquine 4-hydroxylase activity in mouse liver microsomes. Journal of Pharmacology and Experimental Therapeutics. 1997 Sep;282(3):1435-1441.
Masubuchi, Yasuhiro ; Iwasa, Takashi ; Hosokawa, Shin ; Suzuki, Tokuji ; Horie, Toshiharu ; Imaoka, Susumu ; Funae, Yoshihiko ; Narimatsu, Shizuo. / Selective deficiency of debrisoquine 4-hydroxylase activity in mouse liver microsomes. In: Journal of Pharmacology and Experimental Therapeutics. 1997 ; Vol. 282, No. 3. pp. 1435-1441.
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