Adrenal steroid receptor immunoreactivity in cells born in the adult rat dentate gyrus

Several lines of evidence indicate that cell birth in the adult rat dentate gyrus is regulated by adrenal steroids. The expression of adrenal steroid receptors by mitotic cells in the dentate gyrus would support the hypothesis that these hormones act directly on granule cell progenitors. We performed a survival time course of in vivo [³H]thymidine autoradiography combined with immunohistochemistry for mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) and found that very few [³H]thymidine labeled mitotic cells express these receptors. By 4 weeks following [³H]thymidine administration, the vast majority of [³H]thymidine labeled cells were immunoreactive for MR and GR. These results suggest that adrenal steroids do not act directly on granule cell progenitors in the adult rat dentate gyrus.