Gonadal steroids regulate number of astrocytes immunostained for glial fibrillary acidic protein in mouse hippocampus.
The aim of this study was to determine the effect of sex and sex steroids on the distribution of glial fibrillary acidic protein (GFAP) -containing astrocytes in the hippocampal CA1 region of normal, testicular feminized (Tfm/Y) and hypogonadal (hpg) mice. The number of GFAP-immunoreactive (GFAP-IR) cells, assessed by immunohistochemistry, was significantly higher in Tfm/Y and hpg mice than in normal mice. There was no significant sex difference in numbers of GFAP-IR cells in either strain, and no effect of gonadectomy on GFAP-IR cell number in normal mouse hippocampus. In adult male hpg mice, the higher GFAP expression was reduced to normal following treatment with either testosterone or estradiol-17beta, but not 5alpha-dihydrotestosterone. Administration of testosterone from birth significantly reduced the number of hippocampal GFAP-IR cells in both normal and hpg adult mice. These data strongly suggest that the increased number of GFAP-IR astrocytes in the hippocampus is due to the congenital absence of gonadal steroids in hpg mice and androgen insensitivity in Tfm/Y mice. Our findings have important implications for our understanding of the sex steroid modulation of astrocyte reactivity and show that a remarkable degree of plasticity is retained throughout life.
McQueen
J K
JK
MRC Brain Metabolism Unit, Department of Pharmacology, University of Edinburgh, 1 George Square, Edinburgh EH8 9JZ, Scotland.
Dow
R C
RC
Fink
G
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