2.

The levels of human interleukin-1 receptor antagonist (hIL-1ra) in hippocampus (A, B), parietal cortex (C, D) and cerebellum (E, F) of male and female mice with transgenic expression of human soluble IL-1ra (hsIL-1ra) with homozygotic (Tg hsIL-1ra^+/+) and heterozygotic (Tg hsIL-1ra^+/−) genotype, and of wild type (WT) mice. The levels are gene dosage-dependent in all the three brain regions (A–F; statistical data given in Results). In the hippocampus, female mice have higher levels than male mice (*P < 0.001) (A). An age-dependent increase is seen in the parietal cortex of homozygotic mice (*P < 0.001) (D).