Direct effect of methimazole on rat thyroidal cell growth induced by thyrotropin and insulin-like growth factor I.
The direct effect of methimazole (MMI) on FRTL-5 cell growth was examined. TSH, (Bu)2cAMP, calf serum, insulin-like growth factor I, and Graves' immunoglobulin (IgG) increased [3H]thymidine incorporation into DNA during 72-h incubation. MMI (10(-3) M), which does not damage cell viability, significantly enhanced the increase in [3H]thymidine incorporation induced by TSH and (Bu)2cAMP. In contrast, MMI suppressed the increase in [3H]thymidine incorporation induced by calf serum, insulin-like growth factor I, and Graves' IgG. MMI had no effect on the production of cAMP by TSH. Accordingly, we concluded that MMI has opposite effects on cAMP- and non-cAMP-dependent cell growth pathways. Moreover, Graves' IgG, which has a modest effect on cAMP production, is believed to induce cell growth via the non-cAMP dependent cell growth pathway.
Taniguchi
S
S
First Department of Internal Medicine, Tottori University School of Medicine, Yonago, Japan.
Yoshida
A
A
Mashiba
H
H
D000818:Animals; D001696:Biomechanical Phenomena; D003994:Bucladesine / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002999:Clone Cells; D000242:Cyclic AMP / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D006111:Graves Disease / Q000097:blood; D007074:Immunoglobulin G / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000037:antagonists & inhibitors / Q000502:physiology*; D008713:Methimazole / Q000494:pharmacology*; D051381:Rats; D013002:Somatomedins / Q000502:physiology*; D013936:Thymidine / Q000378:metabolism; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D013972:Thyrotropin / Q000502:physiology*
D007074:Immunoglobulin G; D013002:Somatomedins; D008713:Methimazole; D003994:Bucladesine; D007334:Insulin-Like Growth Factor I; D013972:Thyrotropin; D000242:Cyclic AMP; D013936:Thymidine