Factors influencing glycosaminoglycan synthesis by calf trabecular meshwork cell cultures.

When cell or explant cultures were established from excised calf aqueous outflow pathway tissue and subsequently labeled with radioactive precursors of glycosaminoglycans [( 3H]glucosamine and [35S]sulfate), hyaluronic acid was the predominant glycosaminoglycan produced initially. As the cultures reached confluence, sulfated glycosaminoglycans became more prominent products. Further investigation revealed that the cultured trabecular cells could synthesize all of the glycosaminoglycans found in isolated calf trabecular tissue once a critical cell density had been attained. Increasing concentrations of fetal bovine serum in the culture medium stimulated glycosaminoglycan accumulation without altering the quantitative distribution of the various glycosaminoglycan products. Treatment of confluent monolayers with enzymes capable of degrading extracellular matrix molecules caused marked changes in the distribution of glycosaminoglycans produced by calf trabecular-cell cultures. The results suggest that calf trabecular cell cultures can be used to study the dynamics of extracellular matrix production and turnover under controlled experimental conditions.