Impaired neurogenesis in the growth-retarded mouse is reversed by T3 treatment

Triiodothyronine (T-3) regulates neuronal development, and T-3 deficiency impairs the formation of the central nervous system during childhood. Here, we used the hypothyroidal growth-retarded (grt) mouse to investigate whether the generation of new neurons is affected by T-3 deficiency. Cell proliferation in the hippocampus, as measured by 5-bromo-2'-deoxyuridine (BrdU) incorporation, was markedly decreased in the grt mouse while the number of BrdU-positive cells in T-3-treated grt mice was equivalent to that of wild type mice. The cellular differentiation rate did not differ among the experimental groups. These results suggest that T-3 plays an important role during neurogenesis. (C) 2005 Lippincott Williams Wilkins.