Johnson A E, Nock B, McEwen B S, Feder H H
Rockefeller University, New York, NY 10021.
Brain Res. 1988 Mar 1;442(2):205-13. doi: 10.1016/0006-8993(88)91505-3.
Noradrenergic transmission mediated by alpha 1-receptors is involved in the regulation of ovarian steroid-dependent reproductive processes in female guinea pigs. In addition, estradiol treatment is known to affect alpha 2-receptor binding in some steroid-sensitive regions of guinea pig brain. In these experiments, we further assessed the effects of ovarian hormones on alpha-noradrenergic receptors with quantitative autoradiographic methods. Binding of alpha 1- and alpha 2-noradrenergic receptors was measured in male and female guinea pigs treated with either estradiol or oil to determine if sex differences in steroid sensitivity might be related to differences in the distribution or modulation of alpha-receptors. In a second experiment, the possibility was tested that progesterone might alter the sensitivity to norepinephrine by modulating alpha 1- or alpha 2-receptor binding in estradiol-primed female guinea pigs. Results of these studies showed that estradiol treatment reduced alpha 1- and alpha 2-receptor binding of the ventromedial hypothalamic nucleus only in females and increased alpha 2-receptor binding in several preoptic nuclei of both sexes. Progesterone administration, however, had no effect on either alpha-receptor subtype. These studies indicate that estradiol-induced changes in alpha-receptor binding might be involved in steroid-dependent reproductive processes and in the differential responsiveness of males and females to ovarian hormones. Changes in these receptors do not appear to be involved in the stimulatory effects of progesterone on neuroendocrine processes.
由α1受体介导的去甲肾上腺素能传递参与雌性豚鼠卵巢甾体激素依赖性生殖过程的调节。此外，已知雌二醇处理会影响豚鼠脑某些甾体激素敏感区域的α2受体结合。在这些实验中，我们用定量放射自显影方法进一步评估了卵巢激素对α-去甲肾上腺素能受体的影响。在用雌二醇或油处理的雄性和雌性豚鼠中测量α1和α2去甲肾上腺素能受体的结合，以确定甾体激素敏感性的性别差异是否可能与α受体的分布或调节差异有关。在第二个实验中，测试了孕酮是否可能通过调节经雌二醇预处理的雌性豚鼠的α1或α2受体结合来改变对去甲肾上腺素的敏感性。这些研究结果表明，雌二醇处理仅降低雌性腹内侧下丘脑核的α1和α2受体结合，并增加两性几个视前核中的α2受体结合。然而，孕酮给药对任何一种α受体亚型均无影响。这些研究表明，雌二醇诱导的α受体结合变化可能参与甾体激素依赖性生殖过程以及雄性和雌性对卵巢激素的不同反应性。这些受体的变化似乎不参与孕酮对神经内分泌过程的刺激作用。
