J. Golstein et Je. Dumont, CYTOTOXIC EFFECTS OF IODIDE ON THYROID-CELLS - DIFFERENCE BETWEEN RAT-THYROID FRTL-5 CELL AND PRIMARY DOG THYROCYTE RESPONSIVENESS, Journal of endocrinological investigation, 19(2), 1996, pp. 119-126
In order to investigate whether the cytotoxic effect of iodide observe
d in the thyroid gland represented an apoptotic phenomenon, in vitro e
xperiments were performed using the FRTL-5 thyroid cell line and dog t
hyrocytes in primary culture. These cells were exposed to iodide under
various incubation conditions. Apoptosis was assessed through the ana
lysis of DNA breakdown, i.e. the electrophoresis of internucleosomal D
NA fragments generating a typical ''ladder'' and quantification of pre
labelled DNA cleavage products, The FRTL-5 cells appeared to be sensit
ive only to high doses of iodide, far in excess of physiological level
s. They exhibited the different characteristics of two different cell
death phenomena: apoptosis and necrosis. The toxicity of iodide appear
ed to be partially relieved by anti-thyroid agents. This effect consti
tutes an additional example of the general paradigm of iodide action t
hrough oxidized intermediates. In contrast dog thyrocytes in primary c
ulture did not appear to be sensitive to iodide under similar incubati
on conditions; species differences and/or types of culture could accou
nt for these discrepant effects.