Influence of lithium on growth and viability of thyroid follicular cells.
Lithium accumulates in the thyroid gland and can cause goiter or thyroid dysfunction. The aims of our work were: 1) to verify whether lithium stimulates proliferation of thyroid cells; as methods, the 3H-thymidine incorporation assay and the MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) were used; as a model system the FRTL-5 (Fischer rat thyroid cells in low serum) cell line was selected, 2) to test whether lithium can have a cytotoxic effect on FRTL-5 cells, using the cytotoxicity assay with 51Cr release and the trypan blue exclusion method. Without TSH stimulation, lithium at 0.35-2 mM concentrations significantly increased the 3H-thymidine incorporation. A similar effect was observed in the case of the MTT assay: without TSH stimulation, lithium at 0.4-2 mM concentrations showed a significant stimulation of proliferation. Surprisingly, under TSH stimulation, lithium at the 2 mM concentration significantly inhibited proliferation of FRTL-5 cells. With the cytotoxicity assay, lithium was found to increase 51Cr release at 1.4-2 mM concentrations. Additionaly, the percentage of viable FRTL-5 cells at 0.35-2 mM concentrations of lithium was lower than in the controls without lithium. In conclusion, lithium was found to stimulate proliferation of FRTL-5 cells in conditions without TSH and, surprisingly, lithium in higher concentrations diminished proliferation of FRTL-5 cells under TSH stimulation. A cytotoxic effect of higher lithium concentrations was observed.
Gaberscek
S
S
Medical Centre Ljubljana, Department for Nuclear Medicine, Slovenia. simona.gaberscek@kclj.si
Kalisnik
M
M
Pezdirc
M
M
Pavlin
K
K
Hojker
S
S
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002860:Chromium Radioisotopes; D008094:Lithium / Q000494:pharmacology*; D051381:Rats; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D013961:Thyroid Gland / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D013972:Thyrotropin / Q000494:pharmacology
D002860:Chromium Radioisotopes; D013778:Tetrazolium Salts; D013844:Thiazoles; D013972:Thyrotropin; D008094:Lithium; C022616:thiazolyl blue; D013936:Thymidine