Table 6. Effects of the restraint stress induced by the nose-only fluorene exposure device.

Variable	Freely-moving rats	Restrained controls
Physiological endpoints
Body weight (g)
day before starting the habituation to the tubes	243.22±2.01	246.89±2.48
day before starting the exposure	282.56±3.45	270.61±2.95 #
after 7 days of exposure	303.00±4.56	288.56±4.10 #
after 14 days of exposure	317.83±5.41	299.00±4.97 #
Relative brain weight (% b.w.)	0.59±0.01	0.60±0.03
Relative liver weight (% b.w.)	3.15±0.09	2.95±0.05
Relative surrenal gland weight (% b.w.)	0.013±0.002	0.020±0.003
Levels of corticosterone (ng/ml)
day before starting the habituation to the tubes	299.14±32.42	248.55±22.20
day before starting the exposure	283.42±16.19	278.27±15.13
after 7 days of exposure	252.25±21.91	278.08±14.37
after 14 days of exposure	163.25±30.99	193.33±15.05
Behavioral measurements
Total number of crossed cases in the open-field	117.8±10.5	149.2±8.1 #
Total arm entries in the Y-maze	25.3±1.1	32.6±1.6 ##

Results are expressed as mean ± S.E.M. of n = 12 rats/group. ## p<0.01, #p<0.05, statistical significant differences between freely-moving animals and restrained controls (Student t-test). Abbreviations: b.w., body weight.