Regioselective contribution of the cytochrome P-450 2D subfamily to propranolol metabolism in rat liver microsomes

Y. Masubuchi, N. Kagimoto, S. Narimatsu, S. Fujita, T. Suzuki

Research output: Contribution to journalArticle

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Abstract

The metabolism of propranolol was examined by using microsomes from Dark Agouti rats known as a poor-metabolizer animal model for debrisoquine 4- hydroxylation and Wistar rats. Propranolol 4- and 5-hydroxylations followed biphasic Michaelis-Menten kinetics, and 7-hydroxylation and N- desisopropylation were monophasic in both strains. The kinetic studies showed that the V(max) for propranolol 7-hydroxylase activity and the V(max) of high-affinity phases for propranolol 4- and 5-hydroxylase activities were markedly low in Dark Agouti rats compared with those in Wistar rats. The antibody against a cytochrome P-450 isozyme, P-450BTL (Suzuki, T., et al., Drug Metab. Dispos. 20, 367-373, 1992), belonging to the CYP2D subfamily, inhibited by 90% propranolol 4-, 5-, and 7-hydroxylase activities in liver microsomes from male Wistar rats at a low propranolol concentration (5 μM). However, less inhibitory effects of the antibody on propranolol 4- and 5- hydroxylase activities were observed at a high propranolol concentration (1 mM), whereas a similar inhibitory effect of the antibody on propranolol 7- hydroxylase activity was shown. The antibody inhibited propranolol N- desisopropylase activity, but less extent of the inhibition on this activity than those on ring-hydroxylase activities was observed at the low and high propranolol concentrations. These results indicate that a polymorphic cytochrome P-450 isozyme(s) belonging to the CYP2D subfamily is involved predominantly in propranolol 4-, 5-, and 7-hydroxylations at low substrate concentrations in the rat.

Original languageEnglish
Pages (from-to)1012-1016
Number of pages5
JournalDrug Metabolism and Disposition
Volume21
Issue number6
Publication statusPublished - 1993
Externally publishedYes

Fingerprint

Liver Microsomes
Metabolism
Propranolol
Liver
Cytochrome P-450 Enzyme System
Rats
Mixed Function Oxygenases
Hydroxylation
Wistar Rats
Antibodies
Isoenzymes
Debrisoquin
Kinetics
Microsomes
Animals
Animal Models

ASJC Scopus subject areas

  • Pharmacology
  • Toxicology

Cite this

Masubuchi, Y., Kagimoto, N., Narimatsu, S., Fujita, S., & Suzuki, T. (1993). Regioselective contribution of the cytochrome P-450 2D subfamily to propranolol metabolism in rat liver microsomes. Drug Metabolism and Disposition, 21(6), 1012-1016.

Regioselective contribution of the cytochrome P-450 2D subfamily to propranolol metabolism in rat liver microsomes. / Masubuchi, Y.; Kagimoto, N.; Narimatsu, S.; Fujita, S.; Suzuki, T.

In: Drug Metabolism and Disposition, Vol. 21, No. 6, 1993, p. 1012-1016.

Research output: Contribution to journalArticle

Masubuchi, Y, Kagimoto, N, Narimatsu, S, Fujita, S & Suzuki, T 1993, 'Regioselective contribution of the cytochrome P-450 2D subfamily to propranolol metabolism in rat liver microsomes', Drug Metabolism and Disposition, vol. 21, no. 6, pp. 1012-1016.
Masubuchi, Y. ; Kagimoto, N. ; Narimatsu, S. ; Fujita, S. ; Suzuki, T. / Regioselective contribution of the cytochrome P-450 2D subfamily to propranolol metabolism in rat liver microsomes. In: Drug Metabolism and Disposition. 1993 ; Vol. 21, No. 6. pp. 1012-1016.
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