Table 2. Blood and brain concentrations of fluorene and monohydroxylated metabolites.

Variable	Freely-moving rats	Restrained controls	1.5 ppb	150 ppb	ANOVA
					F(3, 20)	p
Blood (ng/mL)
Fluorene	72.6±11.3	70.8±22.5	56.4±22.3	35.6±8.9	0.904	n.s.
9-OH fluorene	0.98±0.13	1.42±0.21	0.75±0.21	3.80±0.46 *	27.007	<0.01
3-OH fluorene	n.d.	n.d.	< LOQ	2.48±0.57 **	22.335	<0.01
2-OH fluorene	n.d.	n.d.	1.10±0.15 **	105.0±18.4 **	39.095	<0.01
Brain (ng/g tissue)
Fluorene	34.121±2.38	31.97±2.28	21.13±3.68 **	19.82±0.31 **	8.763	<0.01
9-OH fluorene	0.68±0.06	0.76±0.26	0.54±0.02	1.35±0.23 *	4.116	<0.05
3-OH fluorene	n.d.	n.d.	n.d.	n.d.	–	–
2-OH fluorene	n.d.	n.d.	< LOQ	0.55±0.09 **	24.417	<0.01

Results are expressed as mean ± S.E.M. of n = 6 rats/group. Dunnett's t-test was used for multiple comparisons. ** p<0.01, * p<0.05, statistical significant differences from restrained controls. Abbreviations: n.d., non detectable, n.s., non significant, LOQ, limit of quantification.