MYOCARDIAL EXPRESSION OF THE TUMOR-SUPPRE SSOR GENE RETINOBLASTOMA SUSCEPTIBILITY GENE - A POTENTIAL CONTROL OF CARDIAC-HYPERTROPHY

Terminal differentiated muscle cells do not enter the cell cycle after growth factor stimulation. This may be an important mechanism of the development of cardiac hypertrophy. In this study we investigated the transcription of the retinoblastoma susceptibility gene (RB), an impor tant antiproliferative factor of the cell cycle, in myogenic cells. RB -transcript and the protein could be detected in myogenic cell lines a nd cardiomyocytes. Incubation of myogenic cells with insulin as an hyp ertrophic stimulus led to a rapid and transient accumulation of the RB protein. We conclude that RB could play an important role as an antip roliferative factor in the myocardium and that it might be involved in the inhibition of mitosis in the development of cardiac hypertrophy.