Gorski R A
Can J Physiol Pharmacol. 1985 Jun;63(6):577-94. doi: 10.1139/y85-098.
The mammalian brain appears to be inherently feminine and the action of testicular hormones during development is necessary for the differentiation of the masculine brain both in terms of functional potential and actual structure. Experimental evidence for this statement is reviewed in this discussion. Recent discoveries of marked structural sex differences in the central nervous system, such as the sexually dimorphic nucleus of the preoptic area in the rat, offer model systems to investigate potential mechanisms by which gonadal hormones permanently modify neuronal differentiation. Although effects of these steroids on neurogenesis and neuronal migration and specification have not been conclusively eliminated, it is currently believed, but not proven, that the principle mechanism of steroid action is to maintain neuronal survival during a period of neuronal death. The structural models of the sexual differentiation of the central nervous system also provide the opportunity to identify sex differences in neurochemical distribution. Two examples in the rat brain are presented: the distribution of serotonin-immunoreactive fibers in the medial preoptic nucleus and of tyrosine hydroxylase-immunoreactive fibers and cells in the anteroventral periventricular nucleus. It is likely that sexual dimorphisms will be found to be characteristic of many neural and neurochemical systems. The final section of this review raises the possibility that the brain of the adult may, in response to steroid action, be morphologically plastic, and considers briefly the likelihood that the brain of the human species is also influenced during development by the hormonal environment.
哺乳动物的大脑似乎天生具有女性化特征，在发育过程中睾丸激素的作用对于男性化大脑在功能潜力和实际结构方面的分化是必要的。本讨论将回顾这一观点的实验证据。最近在中枢神经系统中发现的明显结构性别差异，如大鼠视前区的性二态核，为研究性腺激素永久改变神经元分化的潜在机制提供了模型系统。虽然这些类固醇对神经发生、神经元迁移和分化的影响尚未被完全排除，但目前人们认为（但尚未得到证实），类固醇作用的主要机制是在神经元死亡期间维持神经元存活。中枢神经系统性别分化的结构模型也为识别神经化学分布中的性别差异提供了机会。本文给出了大鼠大脑中的两个例子：视前内侧核中5-羟色胺免疫反应纤维的分布，以及室周腹前核中酪氨酸羟化酶免疫反应纤维和细胞的分布。很可能会发现许多神经和神经化学系统都具有性别二态性。本综述的最后一部分提出了一个可能性，即成年大脑可能会因类固醇的作用而在形态上具有可塑性，并简要考虑了人类大脑在发育过程中也受到激素环境影响的可能性。
