Thyroglobulin gene expression is regulated by insulin and insulin-like growth factor I, as well as thyrotropin, in FRTL-5 thyroid cells.
In FRTL-5 thyroid cells depleted of thyrotropin, insulin, and serum for 3 days, growth and synthesis of thyroglobulin are inhibited. Readdition of insulin or IGF-I in the absence of thyrotropin stimulates thyroglobulin synthesis or thyroglobulin mRNA level by 2-4-fold but has no effect on cell growth. The half-maximal effects of insulin and IGF-I are at 100 and 10 ng/ml, respectively. In both cases, the increased mRNA levels are accompanied by an increase in transcription rate. Maximally effective concentrations of insulin or IGF-I are additive with thyrotropin in increasing thyroglobulin mRNA levels and in increasing transcription; in contrast, the effect of insulin is not additive with IGF-I.
D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004347:Drug Interactions; D005786:Gene Expression Regulation / Q000187:drug effects*; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007700:Kinetics; D012333:RNA, Messenger / Q000096:biosynthesis; D013002:Somatomedins / Q000494:pharmacology*; D013954:Thyroglobulin / Q000235:genetics*; D013972:Thyrotropin / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects
D007328:Insulin; D012333:RNA, Messenger; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D013972:Thyrotropin; D013954:Thyroglobulin