The interactions of glycosaminoglycans (GAGs) with collagen are thought to be important in cell adhesion and cell differentiation. To investigate whether the interactions of GAG or sulfated polysaccharide with collagen can maintain the functions of cultured primary rat hepatocytes, GAG- or sulfated polysaccharide-containing collagen gels were reconstituted in vitro and used for culture of hepatocytes. Among the GAGs and sulfated polysaccharides examined, heparin- and lambda carrageenan-containing collagen gels were found to be able to stimulate and sustain albumin synthesis, while the other GAG- or sulfated polysaccharide-containing collagen gels had almost no effect on maintenance of albumin synthesis. In the cultures using collagen gels that contained 400 micrograms/ml heparin or 100 micrograms/ml lambda carrageenan, albumin synthesis by rat hepatocytes was prolonged to about 4 and 5 weeks, respectively, but albumin synthesis was kept up for only one week in the cultures using conventional collagen gels. These results suggest that the interactions of heparin or lambda carrageenan might be of importance for long-term maintenance of hepatocyte functions.