Panzica GianCarlo, Mura Elena, Pessatti Marzia, Viglietti-Panzica Carla
Rita Levi Montalcini Center for Brain Repair, Laboratory of Neuroendocrinology, Department of Anatomy, Pharmacology and Forensic Medicine, University of Torino, c.so M. D'Azeglio 52, 10126 Torino, Italy.
Domest Anim Endocrinol. 2005 Aug;29(2):436-45. doi: 10.1016/j.domaniend.2005.02.010. Epub 2005 Feb 19.
The copulatory behavior and the parvocellular vasotocin (VT) system of the nucleus of the stria terminalis (BST) are sexually dimorphic in the Japanese quail. Embryonic administration of estradiol benzoate (EB) induces an organizational effect determining the disappearance of such a dimorphism (male shows behavior and cerebral phenotype of the female). The VT parvocellular system can therefore be considered an accurate marker of the sexual differentiation of brain circuits and a very sensitive indicator of the activity of estrogen-like substances on neural circuits. To test this hypothesis we administered diethylstilbestrol (DES), a powerful synthetic xenoestrogen, genistein (GEN), a phytoestrogen produced by soy, and bisphenol A (BPA). After 3 days of incubation, quail eggs were injected with vehicle, EB, DES, GEN or BPA. Administration of BPA caused an early blockage of development and no further analyses were done on the BPA groups. At puberty, the copulatory behavior of EB- or DES-treated male quail was totally abolished, whereas only the highest doses of GEN determined a significant decrease of the behavior. After the tests, the animals were sacrificed and perfused. The fractional area (FA) covered by VT immunoreactivity was analyzed in BST, medial preoptic nucleus, and lateral septum by computerized image analysis. The FA was significantly reduced after treatment with EB, DES and GEN at high doses. These results confirm that the sexually dimorphic VT system of the Japanese quail is a sensible indicator of the effects of xenoestrogens at the level of the central nervous system.
在日本鹌鹑中，终纹床核（BST）的交配行为和小细胞血管紧张素（VT）系统具有性别二态性。胚胎期给予苯甲酸雌二醇（EB）会产生一种组织效应，导致这种二态性消失（雄性表现出雌性的行为和脑表型）。因此，VT小细胞系统可被视为脑回路性别分化的精确标志物，以及雌激素样物质对神经回路活性的非常敏感的指标。为了验证这一假设，我们给予了己烯雌酚（DES，一种强大的合成外源性雌激素）、染料木黄酮（GEN，一种由大豆产生的植物雌激素）和双酚A（BPA）。孵化3天后，给鹌鹑蛋注射溶剂、EB、DES、GEN或BPA。BPA的给药导致发育早期受阻，因此未对BPA组进行进一步分析。在青春期，接受EB或DES处理的雄性鹌鹑的交配行为完全消失，而只有最高剂量的GEN导致该行为显著减少。测试后，处死动物并进行灌注。通过计算机图像分析，在终纹床核、内侧视前核和外侧隔中分析VT免疫反应覆盖的分数面积（FA）。高剂量的EB、DES和GEN处理后，FA显著降低。这些结果证实，日本鹌鹑的性别二态性VT系统是外源性雌激素在中枢神经系统水平上作用的敏感指标。
