Acute-phase response of angiotensinogen in rat adjuvant arthritis

The plasma level of angiotensinogen during the chronic phase of inflammation was studied for comparison with those of other acute-phase reactants in rat adjuvant arthritis. In response to a single injection of Freund's complete adjuvant, this level exhibited a transient increase during the first 24 h. By contrast, increased levels of plasma T-kininogen and alpha 2-macroglobulin, typical acute-phase reactions in the rat, were maintained during the 4-week experimental period. These results suggest that the hepatic synthesis of angiotensinogen is stimulated only in the early phase of chronic inflammation, and therefore that the mechanism underlying the acute-phase response of angiotensinogen is distinct from those currently suggested for other acute-phase reactants.