1,25-Dihydroxycholecalciferol modulates 3H-Thymidine Incorporation in FRTL5 Cells

✍ Scribed by Boonsong Ongphiphadhanakul; Susana A. Ebner; Shih Lieh Fang; Antonio Lombardi; Daniel T. Baran; Lewis E. Braverman

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 506 KB
• Volume: 49
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240490314

✦ Synopsis

Abstract

1,25‐dihydroxycholecalciferol (1,25(OH)~2~D~3~) possesses proliferation and differentiation modulating effects in many cell types in vitro. We studied the effect of 1,25(OH)~2~D~3~ on ^3^H‐thymidine incorporation in FRTL5 cells, a cultured rat thyroid follicular cell line. 1,25(OH)~2~D~3~ alone at 10^−11^ and 10^−9^ M exerted no effect on ^3^H‐thymidine incorporation. However, at 10^−7^ M, 1,25(OH)~2~D~3~ slightly enhanced ^3^H‐thymidine incorporation. In the presence of 5% calf serum, 1,25(OH)~2~D~3~ increased ^3^H‐thymidine incorporation induced by calf serum in a dose‐dependent manner. 1,25(OH)~2~D~3~ also enhanced ^3^H‐thymidine incorporation induced by PMA, an extrinsic stimulator of protein kinase C, without directly affecting PMA‐induced protein kinase C translocation. In contrast to the stimulatory effects of 1,25(OH)~2~D~3~ on the calf serum and PMA‐induced ^3^H‐thymidine incorporation, 1,25(OH)~2~D~3~ inhibited the increase in ^3^H‐thymidine incorporation induced by TSH in a dose‐dependent manner. This effect of 1,25(OH)~2~D~3~ on TSH‐induced ^3^H‐thymidine incorporation may be, in part, due to post‐cAMP pathways since 1,25(OH)~2~D~3~ also inhibited the increase in ^3^H‐thymidine incorporation induced by Bu~2~cAMP without affecting the TSH‐induced increase in cAMP. The stimulatory effect of insulin on ^3^H‐thymidine incorporation, a cAMP‐independent process, was also inhibited by 1,25(OH)~2~D~3~. We conclude that 1,25(OH)~2~D~3~ affects ^3^H‐thymidine incorporation in FRTL5 cells raising the possibility of a physiologic role for 1,25(OH)~2~D~3~ in the growth and function of thyroid follicular cells.