Expression of the c-myc proto-oncogene in growth stimulated porcine thyroid follicle cells.

In the present investigation the expression of c-myc in porcine thyroid follicle cells following the incubation with TSH or EGF was studied. EGF did not only have a mitotic effect on thyroid follicles but also increased c-myc mRNA. The increase in c-myc RNA is an early event in EGF stimulated thyroid cells. TSH had no effect on c-myc RNA levels of porcine thyroid cells. EGF-binding and sensitization to the mitotic activity of EGF, however, is increased by TSH. While TSH stimulates cAMP production and functional activity but not growth or c-myc expression of porcine thyroid cells, EGF produces cell division accompanied with c-myc expression.