Lauber M E, Sarasin A, Lichtensteiger W
Institute of Pharmacology, University of Zürich, Switzerland.
Neuroendocrinology. 1997 Sep;66(3):173-80. doi: 10.1159/000127235.
Sex differences in the activity of aromatase cytochrome P450 (CYP19) in the rat brain have been reported during pre- and postnatal development. It is unclear, however, whether these differences are reflected by corresponding differences in specific mRNA levels. To address this question, we have examined aromatase mRNA levels in specific regions of male and female rat brains by means of in situ hybridization (ISH). At prenatal stages of development, i.e. at gestational day 18 (GD18) and GD20, aromatase mRNA was detected in several preoptic, hypothalamic and limbic brain regions. Semiquantitative analysis of aromatase mRNA did not reveal sex differences in any of these regions. In contrast, clear-cut sex differences were determined at postnatal day (PN) 2; male animals expressed significantly more aromatase mRNA in the bed nucleus of stria terminalis (BST) and the sexually dimorphic nucleus of the preoptic area (SDN). Smaller but still significant differences (females > males) were obtained in the medial preoptic area (MPO). At PN6, sex differences of aromatase mRNA signals (males > females) were still present in the BST, but were no longer detectable in the SDN and the MPO. At PN15 and in adult animals, aromatase mRNA levels were similar in BST and medical amygdaloid nucleus of male and female rats. Since aromatase mRNA expression decreases during postnatal development, no ISH signals could be detected anymore in MPO, SDN and ventromedial hypothalamic nucleus. Our results are consistent with the concept that differential regulation of aromatase mRNA expression might be important for the establishment of different neuronal circuitry in male and female animals.
据报道，在大鼠脑内，细胞色素P450芳香化酶（CYP19）的活性在出生前和出生后的发育过程中存在性别差异。然而，尚不清楚这些差异是否反映在特定mRNA水平的相应差异上。为了解决这个问题，我们通过原位杂交（ISH）检测了雄性和雌性大鼠脑内特定区域的芳香化酶mRNA水平。在发育的产前阶段，即妊娠第18天（GD18）和GD20，在几个视前区、下丘脑和边缘脑区检测到了芳香化酶mRNA。对芳香化酶mRNA的半定量分析未发现这些区域存在性别差异。相比之下，在出生后第2天（PN2）确定了明显的性别差异；雄性动物在终纹床核（BST）和视前区性二态核（SDN）中表达的芳香化酶mRNA明显更多。在内侧视前区（MPO）获得了较小但仍显著的差异（雌性>雄性）。在PN6时，BST中仍存在芳香化酶mRNA信号的性别差异（雄性>雌性），但在SDN和MPO中不再可检测到。在PN15和成年动物中，雄性和雌性大鼠的BST和内侧杏仁核中的芳香化酶mRNA水平相似。由于芳香化酶mRNA表达在出生后发育过程中下降，在MPO、SDN和腹内侧下丘脑核中不再能检测到ISH信号。我们的结果与这一概念一致，即芳香化酶mRNA表达的差异调节可能对雄性和雌性动物不同神经回路的建立很重要。
