Fig 2.
Sex differences in 3β-OH hypnosis occur after hormonal maturity. (a) We administered 3β-OH 100 mg kg−1 i.p. to juvenile male (n=8) and female (n=6) mice at P21 and tested for LORR in comparison with adult mice (two-way anova sex by age, Sidak's multiple comparisons; F1,29=8.657, P=0.006).Adult (∗∗∗P<0.001) and juvenile (∗∗∗∗P<0.0001) females lost righting reflex faster than adult males, and P21 males achieved LORR more quickly than adult males (∗∗∗∗P<0.0001). (b) For duration of LORR, there was a significant interaction (F1,29=13.38, P=0.001) showing that adult (∗∗∗∗P<0.0001) and juvenile (∗∗∗∗P<0.0001) females were unresponsive longer than adult males. P21 males were unresponsive longer than adult males (∗∗∗∗P<0.0001) and had similar duration of LORR as P21 females and adult females. (c, d) We gave 3β-OH 100 mg kg−1 i.p. to gonadectomised (GDX) and sham-operated females (n=10 and n=12 sham and GDX, respectively) and males (n=8 and n=11 for sham and GDX, respectively) and tested for LORR. Gonadectomised females did not differ from sham females in time to or duration of LORR (unpaired t-test, P=0.385 and P=0.682). (e,f). However, GDX males lost righting reflex sooner than their sham counterparts (t17=2.416, ∗P=0.027) and were unresponsive longer than sham males, (t17=7.071, ∗∗∗∗P<0.0001). 3β-OH, (3β,5β,17β)-3-hydroxyandrostane-17-carbonitrile; LORR, loss of righting reflex; anova, analysis of variance.