Journal of Neuroscience, Vol 12, 3642-3650, Copyright © 1992 by Society for Neuroscience
Adrenal hormones suppress cell division in the adult rat dentate gyrus
E Gould, HA Cameron, DC Daniels, CS Woolley and BS McEwen
Laboratory of Neuroendocrinology, Rockefeller University, New York, New York 10021.
The rat dentate gyrus is unusual among mammalian brain regions in that it
shows cell birth well into adulthood. During development, dentate gyrus
cell birth is regulated by adrenal steroids. However, it is presently
unknown whether cell division in the adult is also mediated by these same
factors. In order to determine whether this is the case, we combined
adrenalectomy, with or without corticosterone (CORT) replacement, and
3H-thymidine autoradiography, Nissl staining, and immunohistochemistry for
the glial cell markers vimentin and glial fibrillary acidic protein (GFAP)
as well as for the neuronal marker neuron-specific enolase. Removal of
circulating adrenal steroids resulted in a greater density of both
GFAP-immunoreactive and vimentin- immunoreactive cells compared to
sham-operated animals; CORT replacement prevented increases in both of
these cell types. The increase in the density of vimentin-immunoreactive
cells probably resulted from an increase in the birth of these cells, as
adrenalectomized rats showed greater numbers of 3H-thymidine-labeled
vimentin-positive cells compared to sham rats. In contrast, no changes in
the number of 3H-thymidine-labeled GFAP-positive cells were observed with
adrenalectomy, indicating that the increase in this cell type probably does
not involve cell birth. In addition, the density of 3H- thymidine-labeled
cells that were not immunoreactive for either glial cell marker and that
showed neuronal characteristics was dramatically increased with
adrenalectomy. These results suggest that adrenal hormones normally
suppress the birth of both glia and neurons in the adult rat dentate gyrus.