Table 2

Chlorzoxazone-6-hydroxylation and CYP2E1 content in maternal and fetal tissues

Sample	Chlorzoxazone-6-hydroxylation^2-a		CYP2E1 Protein^2-b
Sample	Ad Libitum	Pair-fed	5% Ethanol	Ad Libitum	Pair-fed	5% Ethanol
Maternal liver	0.473 ± 0.04	0.762 ± 0.21	1.62 ± 0.20^2-c	14.1 ± 0.60	13.8 ± 1.2	18.4 ± 1.8^2-d
Maternal brain	<0.001	<0.001	<0.001	0.100 ± 0.02	0.110 ± 0.03	0.081 ± 0.02
Placenta	<0.001	<0.002	<0.001	0.163 ± 0.05	0.126 ± 0.05	0.097 ± 0.02
Fetal liver	0.029 ± 0.004	0.023 ± 0.008	0.026 ± 0.003	0.813 ± 0.22	0.871 ± 0.25	2.24 ± 0.46^2-d
Fetal brain	<0.001	<0.001	<0.001	N.D.	N.D.	N.D.

Reaction mixtures (1 ml) consisted of 250 μg of microsomal protein in 100 mM KPO₄ buffer, pH 7.4, 500 μM chlorzoxazone and 1 mM NADPH. Reactions were started with NADPH and terminated after 30 min at 37°C with 50 μl of 43% phosphoric acid. The metabolite 6-hydroxychlorzoxazone was detected by HPLC analysis. Immunoblots were performed and quantified as described in Materials and Methods.

↵2-a Values are expressed as nmol product formed/min/mg microsomal protein and represent the mean ± S.E.M. of samples from eight animals or litters per treatment group, except the pair-fed group where the mean represents seven animals or litters. Tissue samples from individual litters were pooled to obtain an adequate amount of microsomal protein.
↵2-b Values are expressed as OD/μg microsomal protein ×10² and denote the mean ± S.E.M. of samples from dams or litters.
↵2-c Significantly different from ad libitum and pair-fed (P < .01).
↵2-d Significantly different from ad libitum and pair-fed (P < .05).
N.D., CYP2E1 content was below the limits of detection.