Characterization of serum, liver, and intestinal sialyltransferases from rats treated with colchicine

Abstract

A modified high pressure liquid chromatographic method using lactose (Galβ1 → 4G1c) as an exogenous acceptor has been used to characterize the sialyltransferases known to increase in the serum of colchicine-treated rats. The results show a 10-fold increase of Galβ1 → 4GlcNAc α2 → 6sialytransferase (α2 → 6 ST), whereas the Galβ1 → 3GlcNAc α2 → 3sialyltransferase showed only 1.6-fold increase in the serum after 17 h of colchicine treatment. The sialyltransferase activity in serum using exogenous desialylated, α1-acid glycoprotein as acceptor also showed an eightfold increase. In liver homogenate and Golgi membrane, the sialyltransferase activity when assayed with desialylated α1-acid glycoprotein as acceptor showed a slight decrease after 4 h, but returned to normal level after 17 h. A similar trend was seen when the two transferases were assayed with lactose as acceptor. The antiserum to rat α2 → 6 ST inhibited the sialyltransferase activity in serum, liver, and jejunal incubation medium. Jejunal sections from rats treated with colchicine for 4 h in presence of heated serum showed a decrease of sialyltransferase, with consequent increase of the α2 → 6 ST enzyme activity in the medium. This result suggests that intestinal tissue could be a source of increased serum enzyme activity in colchicine treatment.