Dawson J L, Cheung Y M, Lau R T
Biol Psychol. 1975 Nov;3(3):213-29. doi: 10.1016/0301-0511(75)90036-8.
The purpose of this experiment is to extend these experiments by using varying neonatal hormonal differentiation processes and to examine the effects of these different methods of neonatal feminization on changes in spatial and activity skills. The experiment involved three neonatally feminized groups of male rats: 'castration alone', 'estrogen alone', and 'estrogen injected castrates' together with one female sample, 'testosterone injected castrates', while treated and untreated male and female controls were also used. The data provide partial support for the major hypotheses that neonatal gonadectomy and opposite sex hormones administered to male and female castrated rats (together and independently for males) would reverse the normal sex-associated abilities of the white rate (higher male spatial learning and higher female activity). However, the feminization effect for the male 'estrogen alone' and 'castration alone' experimental groups was much greater than for the male estrogen injected castrates. The masculinized females, testosterone injected castrates, also had higher spatial learning and lower activity levels, while the feminized male's spatial and activity skills were also reversed. This confirmed in part the extent to which neonatal gonadal sex hormones are effective at critical periods of development in programming the brain in terms of sex-associated spatial and activity skills. Adult hormonal replacement therapy was also administered at 12 months and supported the hypothesis that sex hormones in adults would be mainly activational and have less marked effects than the significant directional changes obtained by these neonatal sex hormones and castration techniques.
本实验的目的是通过使用不同的新生期激素分化过程来扩展这些实验，并研究这些不同的新生期雌性化方法对空间和活动技能变化的影响。该实验涉及三组新生期雌性化的雄性大鼠：“仅阉割”、“仅注射雌激素”和“注射雌激素的阉割大鼠”，同时还有一个雌性样本“注射睾酮的阉割大鼠”，另外还使用了未处理和已处理的雄性和雌性对照。数据为主要假设提供了部分支持，即对雄性和雌性阉割大鼠（对雄性单独和联合使用）进行新生期性腺切除术和给予异性激素会逆转白化大鼠正常的与性别相关的能力（雄性空间学习能力较高，雌性活动能力较高）。然而，雄性“仅注射雌激素”和“仅阉割”实验组的雌性化效果比雄性注射雌激素的阉割大鼠要大得多。雄性化的雌性大鼠，即注射睾酮的阉割大鼠，也具有较高的空间学习能力和较低的活动水平，而雌性化雄性大鼠的空间和活动技能也发生了逆转。这部分证实了新生期性腺性激素在发育关键期对大脑进行与性别相关的空间和活动技能编程方面的有效程度。在12个月时还进行了成年期激素替代疗法，这支持了以下假设：成年期性激素主要起激活作用，其影响不如这些新生期性激素和阉割技术所产生的显著方向性变化明显。
