[The study of direct effect of methimazole on thymidine incorporation in FRTL-5 cells].
During the course of treatment of Graves' disease with the anti-thyroid drug, methimazole (MMI), a decrease in a patient's goiter size is sometimes observed. Using rat thyroid cell strain, FRTL-5, the direct effect of MMI on thyroid cell growth was investigated. FRTL-5 cells (2 X 10(5)) were cultured for 48 hours with TSH, (Bu)2 cAMP or forskolin in the presence of [3H]-thymidine. All three stimulators increased cell growth, expressed as [3H]-thymidine incorporation into DNA in a dose-dependent fashion. When FRTL-5 cells were cultured for 48 hours in the presence of MMI at 10(-6)-10(-3) M with these stimulators (TSH 250 microU/ml, (Bu)2 cAMP 10(-3) M, forskolin 10(-5) M), [3H]-thymidine incorporation was suppressed in dose-dependent fashions (MMI 10(-5) M-10(-3) M). From the present study, it is suggested that methimazole directly modulates thyroid cell growth induced by thyroid growth stimulators which are involved in adenylate cyclase-cyclic AMP system and that the site of its action exists beyond cAMP production.
Urabe
M
M
Fourth Department of Internal Medicine, Saitama Medical School, Japan.
D000818:Animals; D003994:Bucladesine / Q000037:antagonists & inhibitors; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005576:Colforsin / Q000037:antagonists & inhibitors; D004247:DNA / Q000378:metabolism; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D008713:Methimazole / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D013936:Thymidine / Q000378:metabolism*; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism*; D013972:Thyrotropin / Q000037:antagonists & inhibitors; D014316:Tritium
D014316:Tritium; D005576:Colforsin; D008713:Methimazole; D003994:Bucladesine; D013972:Thyrotropin; D004247:DNA; D013936:Thymidine