The synthesis of total sulfated glycosaminoglycans (GAG) was stimulated by transforming growth factors (TGF alpha 1.4-fold at 5 ng/ml, and TGF beta 1 2.05-fold at 2.5 ng/ml) in primary cultures of rat liver fat storing cells (FSC). The combination of both TGFs resulted in an additively stimulated synthesis of total sulfated GAG (more than 3-fold), chondroitin sulfate (more than 15-fold) and hyaluronate (3.8-fold), respectively, whereas the formation of dermatan sulfate was unchanged and that of heparan sulfate was slightly reduced. In summary, TGFs were identified as important mediators of stimulated GAG synthesis in those cells of the liver (FSC), which are the primary site of matrix glycoconjugate production.