Davis E C, Shryne J E, Gorski R A
Department of Neurobiology, UCLA School of Medicine, Laboratory of Neuroendocrinology, Brain Research Institute, Los Angeles, California, 90095-1763, USA.
Neuroendocrinology. 1995 Dec;62(6):579-85. doi: 10.1159/000127053.
The volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA) of the rat is several times larger in males than in females. Several studies have established the importance of gonadal steroids perinatally in the sexual differentiation of the SDN-POA as well as a critical period for the permanent influences of exogenous androgen on the volume of the nucleus. Recent preliminary evidence from this laboratory had suggested, however, that the critical period for the effects of the removal of endogenous gonadal steroids on SDN-POA volume may not match that for the administration of exogenous gonadal steroids. A series of experiments was designed to examine further the effects of the removal of endogenous gonadal steroids on adult SDN-POA volume by castrating male rats at various ages. In spite of a rather clear definition of a postnatal critical period for the effects of exogenous steroid administration, the results of this study indicate that the volume of the SDN-POA is sensitive to the removal of endogenous gonadal steroids for a prolonged period of time, extending through at least day 29 postnatally. The data suggest that there may be multiple critical periods for the sexual differentiation of the SDN-POA and reinforce the concept that these critical periods are distinct from those for other sexually differentiated parameters.
大鼠视前区性二态核（SDN-POA）的体积在雄性中比雌性大几倍。多项研究已证实围产期性腺类固醇在SDN-POA的性别分化中的重要性，以及外源性雄激素对该核体积产生永久性影响的关键期。然而，该实验室最近的初步证据表明，去除内源性性腺类固醇对SDN-POA体积影响的关键期可能与给予外源性性腺类固醇的关键期不匹配。设计了一系列实验，通过在不同年龄阉割雄性大鼠，进一步研究去除内源性性腺类固醇对成年SDN-POA体积的影响。尽管对外源性类固醇给药影响的出生后关键期有相当明确的定义，但本研究结果表明，SDN-POA的体积在很长一段时间内对内源性性腺类固醇的去除敏感，至少持续到出生后第29天。数据表明，SDN-POA的性别分化可能存在多个关键期，并强化了这些关键期与其他性别分化参数的关键期不同的概念。
