Xenbase Image ID: 79351

Fig. 9. The TRα selective agonist CO23, but not the TRβ selective agonists GC1 and GC24, increases cell proliferation in the premetamorphic tadpole brain. (A) Quantification of the number of pH3-positive nuclei in the region of the lateral ventricles in tadpoles treated with vehicle (DMSO; control), T3 (10 nM), GC1 (100 nM), GC24 (100 nM) or CO23 (100 nM) for 48 h. Compounds were added to the aquarium water and were replenished after 24 h. The length of both lateral ventricles from each animal was analyzed. Shown are the data from one of two experiments that gave identical results. (P < 0.05; ANOVA; n = 4/treatment). (B) The GC compounds caused external metamorphic changes, thus showing that they had biological activity. Shown are representative tadpoles treated with vehicle (DMSO; control), GC1 or GC24 (100 nM each) for 6 days (all of the T3 treated tadpoles had died by 4 days and thus are not shown; CO23 animals were not analyzed — the effects on brain cell proliferation verified the biological activity of the CO23). The arrows point to the gills, which showed resorption following treatment with GC1 and GC24. Differentiation of the hindlimb digits was observed with both GC1 and GC24 treatment but not in controls (n = 6/treatment). Image published in: Denver RJ et al. (2009) Copyright © 2009. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View

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