Cholecalciferol metabolites attenuate cAMP production in rat thyroid cells (FRTL-5).

A rat thyroid cell line (FRTL-5) was used to study the effect of cholecalciferols on cAMP production. The active cholecalciferol metabolite, calcitriol, caused a reduction in basal and thyrotropin (TSH)-stimulated cAMP production. The inhibitory effects were demonstrated after 1 and 2 days, respectively. The maximum effect on both basal and TSH-stimulated… (More)