Effect of phenobarbital on the oligosaccharide structure of rat alpha-acid glycoprotein.

We have recently shown that the administration of phenobarbital to rats leads to an increased serum alpha 1-acid glycoprotein content with alterations in the relative proportion of the sugar moiety. Therefore, alpha 1-acid glycoprotein was purified from normal (alpha 1-acid glycoproteine N) and phenobarbital-treated rats (alpha 1-acid glycoprotein PB) Glycans were separated by AX-10 chromatography and analysed by gas chromatography. It appears that, compared to alpha 1-acid glycoprotein N, alpha 1-acid glycoprotein PB had a higher carbohydrate content (31.7% compared to 26%) and a non-negligible amount of neutral oligosaccharide (12.2% compared to 1.3%). No tetrasialyl oligosaccharides in alpha 1-acid glycoprotein PB were detected, whereas their relative proportion in alpha 1-acid glycoprotein N was 27%.