[The effects of maternal stress on the aromatase activity in the perinatal rat brain].

To investigate the influences of intrauterine stress on the aromatase activity (AA) in the perinatal rat's brain, mothers underwent 3 grades of stress: saline injection stress (S), light-heat-mild restraint stress (M), and forced immobilization stress (F). The aromatase activities in the offsprings' hypothalamus and amygdala were determined on day 19 of gestation and on the 1st day after birth. In addition, serum levels of testosterone (T) and androstenedione (A) were measured. In males, perinatal levels of T and A decreased with every grade of prenatal stress. In females, T levels were not affected by prenatal stress. Fetal hypothalamic AA on the 19th day of gestation decreased significantly only in male fetuses of group M and F. Neonatal hypothalamic AA on day 1 after birth decreased only in males of all stress groups. Meanwhile, fetal and neonatal AA in the amygdala did not show any changes in either sex. These results indicate that intrauterine stress depletes both serum androgens and hypothalamic AA in the critical period for sexual differentiation of the brain, which mainly regulates the hypothalamic sex differentiation.