Human IL-1Ra gene transfer to primary rat hepatocytes. (A) The levels of human IL-1Ra produced from AdIL-1Ra transfected co-cultured rat hepatocytes. MOI was based on the hepatocyte number (*P < 0.0001 versus MOI 0, 1, 5, and 25). (B) Time course of human IL-1Ra production from co-cultured rat hepatocytes after MOI 125 transfection. (C) Normalized urea and (D) rat albumin synthesis from co-cultured rat hepatocytes without transfection (MOI 0) and with transfection (MOI 125). Results are presented as normalized to non-transfected co-cultures from the same day. IL-1Ra, interleukin-1 receptor antagonist; MOI, multiplicity of infection; AdIL-1Ra, adenoviral vector encoding human IL-1Ra gene. Results are expressed as mean ± SD (n = 3).