Iodide induces transforming growth factor beta 1 (TGF-beta 1) mRNA in sheep thyroid cells.
We examined TGF-beta mRNA levels in primary sheep thyroid cell cultures to determine whether the inhibitory effects of iodide on thyroid cells could be explained by an induction of TGF-beta mRNA and if this induction was mediated by iodine organification. Thyroid cells were incubated with TSH and five additives (insulin, somatostatin, growth hormone, transferrin, and glycyl-L-histidyl-L-lysin) for 2-3 weeks and then were exposed to sodium iodide (NaI) or 1-methylimidazole-2-thiol (methimazole, MMI), or both for 72 h. Iodide at 10(-6) M and 10(-4) M significantly increased the amount of TGF-beta mRNA as determined by Northern blot analysis with a rat TGF-beta 1 cDNA probe. This increase in TGF-beta 1 mRNA was abolished by the addition of methimazole, an inhibitor of organification. These data indicate that the effects of iodide on thyroid growth and function may be mediated by a process that involves organification of iodide and increases in TGF-beta 1 mRNA levels.
Yuasa
R
R
Department of Medicine, University of California, San Diego.
Eggo
M C
MC
Meinkoth
J
J
Dillmann
W H
WH
Burrow
G N
GN
D000704:Analysis of Variance; D000818:Animals; D015152:Blotting, Northern; D066298:In Vitro Techniques; D007455:Iodine / Q000494:pharmacology*; D008713:Methimazole / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis*; D012756:Sheep; D012974:Sodium Iodide / Q000494:pharmacology; D013961:Thyroid Gland / Q000187:drug effects* / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000235:genetics*
D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D008713:Methimazole; D007455:Iodine; D012974:Sodium Iodide