Changes in the amount of myosin and the rate of myosin biosynthesis in vascular cells in culture

: The relative myosin content of aortic cells of newborn rats was estimated cytophotometrically in the course of cultivation using indirect immunofluorescence staining. It should be shown that the average myosin content of the cell population and the number of cells with high myosin content is greatly enhanced when confluency of the cells is reached and proliferation stops. Following the amount of 14C-labelled leucine incorporated in immunoprecipitated myosin during the same period we found that increasing myosin content of the cells results from an enhanced rate of myosin biosynthesis.