Alterations of steroid receptor coactivator-1 (SRC-1) immunoreactivities in specific brain regions of young and middle-aged female Sprague-Dawley rats.

Previous studies have shown that steroid receptor coactivator-1 (SRC-1) is involved in the regulation of Purkinje cell development and motor learning, neural stem cell differentiation and reproductive-related plasticity. It is widely distributed in the adult brain, but the aging-related changes in the brain remain unclear. In this study age-related alterations of SRC-1 expression in female brain were examined. The results showed that striking age-related decreases of SRC-1 were noticed in those regions related to central regulation of motor (substantia nigra, pontine nuclei, lateral reticular nucleus and Purkinje cells, etc.), learning and memory (olfactory bulb, hippocampus, Purkinje cells, etc.), and neural stem cell (olfactory, dentate gyrus, cerebral cortex, etc.). Surprisingly, although SRC-1 immunopositive materials were predominantly detected in the cell nuclei, they were also detected in the extra-nuclear components predominantly in these motor-regulation sub-regions. The above results showing age-related decrease of SRC-1 in specific motor, learning and memory nuclei suggested its potential roles in neurodegenerative disorders, which may be one of the underlying mechanisms of the vulnerability of the aged brain.