Regulation of proto-oncogenes in rat parotid acinar cells in vitro after stimulation of β- adrenergic receptors

Stimulation of β-adrenoreceptors in rat parotid acinar cells in vitro by the β-adrenergic agonist isoproterenol induces steady-state levels of c- fos mRNA and c- fos protein in these cells. A dramatic increase in the steady-state levels of c- fos mRNA was observed at 60 min, followed by a decrease at 2 h with a second peak at 4 h. c- fos induction in rat parotid acinar cells in vitro seems to be mediated by cAMP. Increased levels of p53 and c- myc mRNA were detected only at 60 min. c- abl and c- sis were also induced by isoproterenol but in a pattern different from that seen with c- fos. c- abl was the only oncogene in rat parotid gland which showed increased expression after chronic isoproterenol treatment of rats. In rat parotid acinar cells we observed no correlation between DNA synthesis and c- fos induction.