Johnson A E, Nock B, McEwen B S, Feder H H
Section on Comparative Studies of Brain and Behavior, National Institute of Mental Health, Poolesville, MD 20837.
Brain Res. 1988 Aug 1;470(2):247-52. doi: 10.1016/0165-3806(88)90243-x.
Immature female guinea pigs are relatively insensitive to the effects of ovarian steroids on certain reproductive processes including the facilitation of sexual receptivity and the induction of hypothalamic progestin receptors by estrogen. In adult guinea pigs, alpha-receptor-mediated noradrenergic transmission is known to affect both of these processes. In the experiments reported here, we investigated the possibility that age-related differences in alpha 1- and alpha 2-noradrenergic receptors might underlie the insensitivity of neonates to ovarian steroids. With tritium-sensitive film autoradiography, the distribution of alpha 1- and alpha 2-receptors in neonatal and adult female guinea pigs was compared and the effects of exogenous estradiol-17 beta on alpha-receptor binding was examined in neonatal guinea pigs. The results of these experiments showed that in animals not treated with estrogen the binding of both alpha-receptor subtypes differed between adults and neonates in several brain regions including areas known to be involved in the regulation of reproduction. In all regions where differences occurred, alpha-receptor levels were higher in neonatal females than in adult females. In addition, in contrast to previously reported results in adults, estrogen did not affect alpha-receptor binding in any region of neonatal guinea pig brain.
未成熟的雌性豚鼠对卵巢类固醇对某些生殖过程的影响相对不敏感，这些过程包括促进性接受能力以及雌激素诱导下丘脑孕激素受体。在成年豚鼠中，已知α受体介导的去甲肾上腺素能传递会影响这两个过程。在本文报道的实验中，我们研究了α1和α2去甲肾上腺素能受体的年龄相关差异可能是新生儿对卵巢类固醇不敏感的基础这一可能性。通过氚敏感胶片放射自显影术，比较了新生和成年雌性豚鼠中α1和α2受体的分布，并在新生豚鼠中检测了外源性雌二醇-17β对α受体结合的影响。这些实验结果表明，在未用雌激素处理的动物中，两种α受体亚型的结合在包括已知参与生殖调节的区域在内的几个脑区中，成年和新生动物之间存在差异。在所有出现差异的区域中，新生雌性的α受体水平高于成年雌性。此外，与先前报道的成年动物结果相反，雌激素对新生豚鼠脑的任何区域的α受体结合均无影响。
