“…Only about 4 ± 5 percent of thyroid follicular cells respond, without any change even after a 7 day exposure of high doses of iodide or d-iodolactone. This rapid induction of apoptosis by iodide has already been shown in vivo (Bechtner et al, 1999;Burikhanov and Matsuzaki, 2000) as well as in vitro by H 2 O 2 (Riou et al, 1999;Riou et al, 1998), iodide (Feldkamp et al, 1999), TNF (Bretz et al, 1999) and EGF and TGF-b (Bechtner et al, 1999;Gärtner et al, 1997). The follicular cells in our three dimensional system are functional active, and proliferate only after stimulation with growth factors or after iodide depletion (Gärtner et al, 1985;Bechtner et al, 1996).…”