Effect of Trimethylcolchicinic Acid on the Synthesis and Excretion of Proteoglycans in Tissue Culture

The action of trimethylcolchicinic acid on the synthesis and excretion of proteoglycans has been studied on the L cell strain. The incorporation of precursors has been measured, and proteoglycans produced in the culture medium have been extracted and their concentration determined. The mucopolysaccharide components have been studied by electrophoresis. Control cultures produce hyaluronic acid, dermatan sulfate and very low concentrations of chondroitin 4‐sulphate or 6‐sulphate. Cultures treated with trimethylcolchicinic acid (4 μg/ml) produce hyaluronic acid, very high concentrations of chondroitin 4‐sulphate or 6‐sulphate and only traces of dermatan sulphate. So, trimethylcolchicinic acid does not modify the synthesis of hyaluronic acid; it considerably increases the production of chondroitin 4‐sulphate or 6‐sulphate and inhibits the production of dermatan sulphate. Protein fraction of the proteoglycans is proportionally increased in treated cultures, but there is no marked difference between amino acid concentrations of proteoglycans extracted from control and treated cultures. A slight fall in the cystine concentration was the only change in the amino acid content of proteoglycans extracted from treated cultures. A hypothesis to explain these results is discussed.