Androgen receptors are differentially distributed between right and left cerebral hemispheres of the fetal male rhesus monkey

In humans there are apparent sex differences in verbal and spatial abilities as well as several cortical pathologies. These differences may arise as the result of prenatal androgen exposure and its effect on the development of the cerebral cortex. With this in mind, we have examined androgen receptor (AR), aromatase (AROM) and 5 alpha-reductase (5 alpha R) levels in the cerebral cortex of Day 70 male and female fetal rhesus monkeys (Macaca mulatta). Receptor and enzyme levels were evaluated in both right (Rt) and left (Lft) temporal (TMP) and frontal (FR) lobes of the cerebral cortex. AR levels in FR-Rt of male subjects were higher than levels in FR-Lft (for each and every subject, P less than 0.05), while in females, there was no consistent pattern in the distribution of the receptor between the two sides of FR. In contrast, AR values in TMP-Lft of male subjects were consistently higher than in TMP-Rt (P less than 0.05). As with the FR, females exhibited no consistent pattern in the distribution of AR between the two TMP sides. AROM and 5 alpha R levels were similar, regardless of sex, between both sides of the two cortical lobes indicating that the AR distribution pattern is not a general biochemical phenomenon. The differential cortical distribution of AR in fetal males versus females lends support to the hypothesis that prenatal androgens from the fetal testes may effect the differentiation of sexually dimorphic, side-specific cortical activity.

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