High activity of cytochrome P-450-linked aminopyrine N-demethylase in mouse brain microsomes, and associated sex-related difference.
The presence of cytochrome P-450 and associated mono-oxygenase activities was examined in brain microsomes from male and female mice. Although the cytochrome P-450 level in male mouse brain was very low as compared with mouse liver, the aminopyrine N-demethylase and morphine N-demethylase specific activities in male mouse brain were much higher than those observed in mouse liver. Ethoxycoumarin O-de-ethylase and aniline hydroxylase activities were, however, not detected in mouse brain. Sex-related differences were observed in both the cytochrome P-450 levels and aminopyrine N-demethylase activity in mouse brain, the levels of both being higher in male mouse brain as compared with female mouse brain. Aminopyrine N-demethylase activity in mouse brain microsomes was dependent on the presence of oxygen and NADPH and could be inhibited by piperonyl butoxide, N-octyl imidazole and carbon monoxide. Antiserum raised to the phenobarbital-inducible form of rat liver cytochrome P-450 [P-450(b+e)] inhibited mouse brain aminopyrine N-demethylase activity by around 80+ mouse brain microsomal protein exhibited cross-reactivity against this antiserum when examined by Ouchterlony double diffusion and immunoblotting. The present results indicate the presence of a phenobarbital-inducible form of cytochrome P-450 (or a form of cytochrome P-450 that is similar immunologically) in mouse brain microsomes, which is associated with a sex-related difference.
Ravindranath
V
V
Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences, Bangalore, India.
Ananda Theertha Varada
H K
HK
D000633:Aminopyrine N-Demethylase / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000201:enzymology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005260:Female; D008297:Male; D051379:Mice; D008861:Microsomes / Q000201:enzymology*; D012727:Sex Characteristics
D003577:Cytochrome P-450 Enzyme System; D000633:Aminopyrine N-Demethylase