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 cAMP production was observed after 3-4 days of treatment. The effect was detectable at 10(-10) and maximal at 10(-8) mol/l. Calcitriol was about 300 times more potent than calcidiol in attenuating cAMP production, whereas (24R)-hydroxycalcidiol in concentrations up to 3 x 10(-8) mol/l had no effect. After removal of added calcitriol the cAMP response to TSH returned to normal within 8 days. Calcitriol (10(-8) mol/l) also inhibited cell growth. Our results show that calcitriol at physiological concentrations inhibits both basal and TSH-stimulated cAMP production in rat thyroid cells. This indicates that calcitriol may modulate the effect of TSH on thyroid function and growth.
Berg
J P
JP
Hormone Laboratory, Aker Hospital, Oslo, Norway.
Sørnes
G
G
Torjesen
P A
PA
Haug
E
E
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002117:Calcitriol / Q000494:pharmacology; D002455:Cell Division; D002460:Cell Line; D002762:Cholecalciferol / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis*; D007700:Kinetics; D051381:Rats; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism*; D013972:Thyrotropin / Q000502:physiology
D002762:Cholecalciferol; D005576:Colforsin; D013972:Thyrotropin; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D002117:Calcitriol