Stereoselective propranolol metabolism in two drug induced rat hepatic microsomes

Table 3 Enzymatic kinetic parameters in propranolol enantiomer metab olism in vitro in rat hepatic microsomes induced by β-naphthoflavone or ph enobarbital

Group	Enantiomer	Km μmol/L	Vmax mmol/g/min	Clint L/min/g protein	R( + )Vmax: S( - )Vmax
Control	R( + )	30 ± 8	1.5 ± 0.2b	60 ± 3b	0.5
	S( - )	18 ± 5	2.9 ± 0.3	170 ± 30
BNF	R( + )	34 ± 3	3.8 ± 0.3fh	111.0 ± 1afh	1.14
	S( - )	39 ± 7d	3.3 ± 0.5g	84 ± 5eh
P B	R( + )	38 ± 17	0.07 ± 0.03ef	2.0 ± 2cf	0.038
	S( - )	36 ± 10d	1.94 ± 0.07e	56.0 ± 1e

Clint (intrinsic clearance) is the ratio of V_max/Km, mean ± s, n = 3.

^aP < 0.05,

^bP < 0.01,

^cP < 0.001, compared with S( - ) propranolol;

^dP < 0.05,

^eP < 0.01,

^fP < 0.001, compared with corresponding enantiomer in control group;

^gP < 0.01,

^hP < 0.001, compared with corresponding enantiome r in PB group with unpaired t test.