Mechanism of glycoconjugates biosynthesis in the vascular wall with external circular constraint.

Extrinsic local constraints, realised on dogs aorta are responsible for parietal lesions in the form of thickening of the arterial wall. Histological changes in the intima and media are characteristic of processes of degeneration destruction and cellular regeneration, superposed on sub-endothelial proliferation accompained by partial or total destruction of endothelial cells in the intimal layer. In addition to histological changes, there were perturbation in enzymatic activities of glycosyltransferases responsible for macromolecular constructions in the intima. Microsomic enzymes studied were: N-acetyl-glucosaminyl-transferase, sialyl-transferase and N-acetyl-galactosaminyl-transferase, and two glycosyl-transferases located in the soluble cytoplasmic phase: fucosyl and xylosyl-transferase. The changes observed were different according to the position of the sugars in the glycoprotein chains. For example the variation of fucosyl-transferase activity is significant: it disappears in group where the sialyl-transferase activity is enhanced. The transfer of xylose is decreased. Finally, changes observed in hexosaminyl-transferase activities were parallel.