Changes in glycosaminoglycan, galactosyltransferase-I, and sialyltransferase during rat liver regeneration

After partial hepatectomy, the liver is capable of complete restoration to its normal size. The extracellular matrix, which surrounds the cells, plays important roles in this regeneration. Glycosaminoglycans (GAGs), which are components of the extracellular matrix, interact with several other matrix components and growth factors, and are involved in hepatocyte growth. In this study, the content of heparan sulfate, a major GAG in rat liver, reached a minimum at 12 hours after partial hepatectomy. Galactosyltransferase-I activity, related to the synthesis of GAGs, and sialyltransferase activity, related to the synthesis of glycoconjugates, reached a minimum at 6 hours. The serum and liver contents of hyaluronic acid reached a maximum at 1 day and returned gradually to their preoperative levels. These results suggest that polysaccharide synthesis was decreased in the Golgi apparatus of hepatocytes at the beginning of regeneration, and that hyaluronic acid degradation decreased in the lysosomes of hepatocytes. The ability to synthesize polysaccharides recovered ahead of the ability to degrade hyaluronic acid. The changes in these GAGs with time in the early regeneration period might play an important role in organ regeneration.