| Abstract: | Radioautographs of brain sections were prepared after injection of 3H-thymidine into mice aged 23, 100, 200 or 400 days. The presence of a small number of labeled cells in all animals indicates that neuroglia do proliferate even at an advanced age. Proliferation is most active in the corpus callosum and least so in the corpus striatum. Comparison of the counts of labeled and unlabeled nuclei suggests that glial cells are produced in numbers exceeding growth requirements and, accordingly, that they turn over, although slowly. |
