Abstract
In healthy Nagase analbuminemic rats (NAR), the highest degree of relative increase in serum protein concentration was found for α-2-macroglobulin, the most prominent acute phase protein in rats. Its levels were about 30- and 60-fold higher in males and females, respectively, than those in the control Sprague-Dawley (SD) rats. In terms of absolute concentration, however, α-l-inhibitor 3 (also called α-X-protein or murinoglobulin) showed the most conspicuous change, its levels being higher by about 7 mg/ml than those in SD. When the acute phase reaction was induced by subcutaneous injection of turpentine, the levels of α-1- and α-2-macroglobulins, α-1-cysteine proteinase inhibitor, α-1- antiproteinase, and α-1-inhibitor 3 in NAR changed in essentially the same way as in SD: α-l-inhibitor 3 decreased markedly while the rest increased further. These results suggest that mechanisms responsible for the elevation of serum globulins in healthy NAR are not directly related to those involved in the acute phase response. On the other hand, the antithrombin III levels in healthy NAR were about twice the control values and changed little during the inflammation. In contrast, this protein in SD doubled during the acute phase, its maximal levels being close to those in healthy or inflamed NAR. This suggests that the antithrombin III level in healthy NAR is regulated by a mechanism similar to that in SD maximally reacting to the acute phase stress. Thus, the present results suggest that in healthy NAR, there is no common mechanism giving rise to the elevation of individual globulins, and that the mechanism underlying the acute phase response may be operative, at least to some extent, for a few proteins, but not for most proteins.
