Radial immunodiffusion assay for rat alpha 1-acid glycoprotein

alpha 1-Acid glycoprotein (AGP) is an "acute phase protein" whose expression is altered in several human pathologies. Using antiserum from New Zealand white rabbits, a radial immunodiffusion assay for measuring AGP levels in rat plasma was developed operating in the range of 50-2500 micrograms/ml with high specificity. Standard curves were constructed (precipitin ring diameter 2 vs. micrograms/ml AGP) yielding highly linear plots (r = .98). The plasma concentration of AGP in spontaneously hypertensive (SHR) rats was double that of the normotensive Kyoto-Wistar (WKY) rats (208 +/- 10 vs. 118 +/- 5 micrograms/ml). AGP induction by turpentine resulted in a 14- and 26-fold increase in AGP levels in SHR and WKY rats, respectively. Induction of AGP by dexamethasone injection was examined in the SHR and WKY rat strains resulting in a 5- and 12-fold increase in AGP levels, respectively. AGP concentration in whole brain of rats was determined to be 12.7 +/- 1.8 micrograms/g. AGP concentrations in SHR and WKY liver were also determined to be 159 +/- 3 and 148 +/- 5 micrograms/g liver tissue.