Metabolism of glycosaminoglycans of cultured rat aortic smooth muscle cells altered during subculture.

We observed the changes in the metabolism of glycosaminoglycans of cultured smooth muscle cells from the rat aorta during subculture. The primary culture was achieved by the enzymatic dispersion method. The metabolism of glycosaminoglycans in smooth muscle cells was estimated by measuring the incorporation rate of D-[1-14C] glucosamine and [35S] sulphate. Smooth muscle cells were harvested by trypsinization, and glycosaminoglycans were separately extracted and purified from trypsin digest and cells. In the cells of the stationary phase of primary culture, the incorporation of both D-[1-14C] glucosamine and [35S] sulphate into dermatan sulphate was greater than that into heparan sulphate. However, in the trypsin digest, the incorporation of D-[1-14C] glucosamine and [35S] sulphate into dermatan sulphate was less than and equal to that into heparan sulphate. In both the cells and the trypsin digest, the incorporation of D-[1-14C] glucosamine and [35S] sulphate into heparan sulphate decreased and that into dermatan sulphate increased with increase in the number of passages. These results indicate that there is a development of serial modulation in the metabolism of glycosaminoglycans in the cultured smooth muscle cells, in the early passage of subculture and that such should be taken into consideration when analysing the observations.