After trauma or sepsis, the liver undergoes a reprioritization of export protein synthesis with elevated production of some acute-phase reactants and reduced production of others. We have examined the effects of combinations of insulin and the counterregulatory hormones (dexamethasone, glucagon, and epinephrine), in the presence or absence of interleukin (IL)-6, on the production by isolated hepatocytes of the positive acute-phase proteins C-reactive protein, alpha 1-antichymotrypsin, alpha 1-acid glycoprotein, and haptoglobin, and the negative acute-phase proteins prealbumin and transferrin. The effect of IL-6 on the production of the above proteins was influenced significantly by insulin and all of the counterregulatory hormones. Significant three-way interactions as well as higher order interactions between the stress hormones and insulin were seen in the case of C-reactive protein. The results indicate that both positive and negative acute-phase proteins respond differently to insulin and the counterregulatory hormones and that the potential exists for the regulation of synthesis of individual acute-phase reactants by interaction between the cytokine network and the classical endocrine hormones.