Differential changes in alpha2-macroglobulin and hemopexin in brain and liver in response to acute inflammation

Changes in serum and cerebrospinal fluid (CSF) proteins following generalized acute inflammation induced by fermented yeast in the rat was examined by concanavalin A-blotting, immunoblotting, and radioimmunoassay. Using alpha2-macroglobulin (alpha2-M) and hemopexin (HPX) as marker proteins, the concentration alpha2-M was found to increase in serum and CSF by 150- and 5-fold, respectively, whereas the concentration of HPX increased by about 4-fold in both fluids following yeast-induced inflammation. The lesser increase in alpha2-M in the CSF versus the systemic circulation is not likely to be the result of changes in the permeability of the blood--brain barrier, since no change in the total protein content of CSF was detected in inflamed rats when compared to control animals. These results, however, illustrate the regulation of the same protein, such as alpha2-M, in two separate organs within the same animal can be drastically different. These results also suggest a possible protective role of alpha2-M in the brain during acute inflammation. Moreover, these observations are consistent with the previous observation that there is a differential response in the level of alpha2-M between the testis and the systemic circulation during inflammation.