Neurosteroidogenesis in Astrocytes, Oligodendrocytes, and Neurons of Cerebral Cortex of Rat Brain

The brain is a steroidogenic organ that expresses steroidogenic enzymes and produces neurosteroids. Although considerable information is now available regarding the steroidogenic capacity of the brain, little is known regarding the steroidogenic pathway and relative contributions of astrocytes, oligodendrocytes, and neurons to neurosteroidogenesis. In the present study, we investigated differential gene expression of the key steroidogenic enzymes using RT-PCR and quantitatively evaluated the production of neurosteroids by highly purified astrocytes, oligodendrocytes, and neurons from the cerebral cortex of neonatal rat brains using specific and sensitive RIAs. Astrocytes appear to be the most active steroidogenic cells in the brain. These cells express cytochrome P450 side-chain cleavage (P450scc), 17α-hydroxylase/C17–20-lyase (P450c17), 3β-hydroxysteroid dehydrogenase (3βHSD), 17β-hydroxysteroid dehydrogenase (17βHSD), and cytochrome P450 aromatase (P450arom) and produce pregnenolone (P5), progesterone (...