TABLE 3

Correlation of P450 activities with the metabolism rates of buspirone in a panel of human liver microsomes Buspirone (5 μM) was incubated separately with 16 individual HLM.

Metabolism Reactions	P450 Isoform	Regression Coefficient (r²)
				Metabolite Formation^a					Overall Buspirone Metabolism^b
				1-PP	3′-OH	6′-OH	5-OH	N-oxide	Overall Buspirone Metabolism^b
7-Ethoxyresorufin O-dealkylation	1A2	0.06	0.09	0.07	0.12	0.09	0.09
Coumarin 7-hydroxylation	2A6	0.25	0.25	0.24	0.21	0.18	0.01
S-Mephenytoin N-demethylation	2B6	0.41	0.32	0.50	0.32	0.49	0.40
Diclofenac 4′-hydroxylation	2C9	0.10	0.10	0.09	0.11	0.06	0.03
S-Mephenytoin 4′-hydroxylation	2C19	0.36	0.32	0.31	0.28	0.44	0.35
Dextromethorphan O-demethylation	2D6	0.08	0.08	0.08	0.06	0.09	0.11
Chlorzoxazone 6-hydroxylation	2E1	0.08	0.12	0.08	0.09	0.09	0.13
Testosterone 6β-hydroxylation	3A4	0.96^***	0.92^***	0.93^***	0.85^***	0.86^***	0.92^***

↵ a Data presented in this table were averaged from analyses of duplicate incubations. Statistical significance of the correlation between metabolism rates and P450 enzyme activities is denoted by ^***ρ <0.0005
↵ b The rate of the overall metabolism was calculated based on the conversion of buspirone to the total metabolite peaks