Aromatase cytochrome P450 and 5 alpha-reductase in the amygdala and cortex of perinatal rats.

The major androgen metabolizing enzymes, aromatase cytochrome P450 and 5 alpha-reductase play critical role(s) in the development of sexually dimorphic brain structures, the modulation of neuroendocrine function(s) and the regulation of sexual and non-sexual behaviors. Using established assays, we detected 5 alpha-reductase and aromatase enzymatic activities in amygdala and frontal cortical tissue from male and female rats during the perinatal interval (from gestational day (GD) 19 to postnatal day (PND) 6). The present findings indicate that 5 alpha-reductase and aromatase rates in the cortex display different enzyme profiles, while in the amygdala tissue site a similar pattern is seen for both enzymes during perinatal development. In general, there was a lack of sex differences in the enzymatic rates. The importance these enzyme systems play in generating androgen (and progesterone) steroid metabolites which influence neural development and function are discussed.