Figure 5.

The effect of goitrogens on zebrafish metamorphosis and rescue by T₄. (A) Dorsal and (B) side views of sibling fish fixed and stained with alcian/alizarin on day 33 postfertilization: (Top) control; (Middle) treated continuously from day 4 with 1 mM methimazole; (Bottom) treated similarly with methimazole but rescued by the addition of 30 nM T₄ beginning at day 11. (C) Sibling fish were fixed and stained with alician/alizarin at day 65 postfertilization: (Top) control; (Middle) treated continuously from day 14 with 0.025% KClO₄; (Bottom) treated similarly with KClO₄ but rescued by the addition of 30 nM T₄ beginning at day 56. (Bar = 3 mm.)