2002 Volume 48 Issue 1 Pages 17-23
Androgen, largely through its aromatized estrogen, plays an important role in sexual differentiation of the rat brain during the perinatal period. To demonstrate the regulation of estrogen receptors α (ERα), and β (ER β), androgen receptor (AR), and aromatase (AROM) gene expression, the mRNA levels of these mRNAs were determined in the hypothalamus of male and female rats at 2, 6, and 10 days of age using the competitive RT-PCR method. ERα mRNA level did not differ between males and females, except that gene expression on day 6 was lower in males than in females. There were no significant differences in gene expressions of ERβ and AR in the hypothalamus between males and females throughout the neonatal period. AROM mRNA levels were higher on males for all 3 days of determination. Subcutaneous estrogen treatment at 2 days of age decreased ERα mRNA levels, while it increased ERβ, AR and AROM gene expressions. Our results suggest that sexual differences and steroid-dependent regulation of these genes might be important in the sexual differentiation of the rat brain.
