RT-PCR and cytokine analyses. (A) Gene expression: PRKCZ gene expression did not differ between groups, contrary to the protein level. IRS-1, top right graph, was decreased in the two young groups receiving insulin as compared to the vehicle group Δ (P < 0.05); in the young rats, IL-1β mRNA was increased in the LPS-infused group, *P < 0.01, versus aCSF and decreased, ΔP < 0.03 versus LPS + insulin. TNFα mRNA was increased by LPS infusion, *P < 0.01, versus aCSF and decreased, ΔP < 0.01, versus LPS + insulin. (B) No significant difference, P > 0.05, in the level of TNFα while IL-1β level was increased, *P < 0.01, as compared to aCSF. The aged rats showed no differences, P > 0.05, between aCSF and insulin-infused groups.