Abstract: | The variation of specific activity of adenyl cyclase has been studied during differentiation of an established line of myoblast, strain L6D and of a temperature sensitive developmental variant strain, H6, derived from it. The specific activities of both basal and NaF stimulated adenyl cyclase were found to decrease 2 to 3 folds after fusion of myoblasts into myotubes in cultures of L6D. Cultures of strain H6 displayed the same decrease in specific activity of adenyl cyclase when grown at temperature which allows differentiation, while no decrease was observed at the temperature which does not allow cell fusion. These results indicare that the decrease in specific activity of adenyl cyclase is associated with cell fusion and reflects membrane changes ocurring during differentiation of myogenic cells. |