Figure 4.

Serum S-SMase activity is increased by injection with IL-1β and TNF-α. Wild-type mice were injected i.p. with 0.8 mg/kg human recombinant IL-1β, 0.5 mg/kg human recombinant TNF-α, both, or saline. Serum SMase activity in the presence of Zn²⁺ was assayed 3 h after cytokine or saline injection in A and 0.5–3 h after combined cytokine (○) or saline (●) injection in B. In A, there were seven mice in the saline group and four mice in each of the other groups. Each of the six possible pairwise comparisons between groups in A indicated a significant difference (P < 0.01). In B, there were three mice in each group; the 1.5- and 3-h values from the combined cytokine group were statistically different (P < 0.05) from the respective saline values.