Experimental manipulation of sexual differentiation in wallaby pouch young treated with exogenous steroids.
Experimental manipulation of sexual differentiation in wallaby pouch young treated with exogenous steroids.
复制标题
用外源类固醇处理的小袋鼠育儿袋幼崽性别分化的实验操作。
作者：
G. Shaw;M. Renfree;R. Short;W. O
我们研究了从出生当天（此时性腺在组织学上未分化）到育儿袋生活的第25天（此时性腺以及中肾管和苗勒氏管已分化，睾丸已通过腹股沟管迁移）对雌性或雄性塔马尔沙袋鼠进行雄激素或雌激素处理的效果。雌性塔马尔沙袋鼠口服丙酸睾酮（24 - 50毫克/千克/天）25天，其中肾管和苗勒氏管增大。然而，乳腺和育儿袋的发育与对照雌性没有区别。该处理对卵巢发育或腹部卵巢位置没有明显影响。雄性和雌性的阴茎大小相似，并且在第25天两种实验处理对其大小都没有显著影响。雄性塔马尔沙袋鼠口服苯甲酸雌二醇（1.2 - 2.5毫克/千克/天）25天，泌尿生殖窦明显肥大。睾丸形态异常；许多生殖细胞看起来坏死，生精小管直径减小，间质细胞很少，小管之间纤维组织增多。这些性腺的皮质包含一些具有卵巢外观的区域，没有小管且含有大量生殖细胞。对照雄性的苗勒氏管已经退化，但雌激素处理阻止了这种退化，这表明要么是苗勒氏管抑制物质（MIS）的产生受到抑制，要么是其作用受到抑制。处理过的雄性正常的睾丸迁移受到抑制；睾丸在腹部位置较高，与对照雌性的卵巢位置相似，而对照雄性的睾丸都在腹股沟区域。对照雄性的引带和鞘突延伸到阴囊，但在处理过的雄性中它们在阴囊外终止。雌激素处理对阴囊大小没有影响，也没有诱导乳腺或育儿袋发育。这些实验表明，有袋类动物像真兽类动物一样，对中肾管和苗勒氏管的发育有双重激素控制。相比之下，乳腺、育儿袋、引带和阴囊的初始发育似乎不受激素控制，因此可能是自主的且依赖于基因型。
We have investigated the effects of androgen or oestrogen treatment of female or male tammar wallabies from the day of birth, when the gonads are histologically undifferentiated, to day 25 of pouch life, when the gonads and the Wolffian and Müllerian ducts have differentiated and the testes have migrated through the inguinal canal. Female tammars treated with testosterone propionate (24-50 mg kg-1 day-1) orally for 25 days had enlarged Wolffian and Müllerian ducts. Mammary and pouch development, however, was indistinguishable from that of control females. The treatment had no apparent effect on ovarian development, or on ovarian position in the abdomen. The phallus of males and females was similar in size, and neither experimental treatment had a significant effect on its size at day 25. Male tammars treated with oestradiol benzoate (1.2-2.5 mg kg-1 day-1) orally for 25 days had gross hypertrophy of the urogenital sinus. Testicular morphology was abnormal; many of the germ cells appeared necrotic, the seminiferous tubules were of reduced diameter, and there were few Leydig cells and increased amounts of fibrous tissue between the tubules. The cortex of these gonads contained some areas which had an ovarian appearance, lacking tubules and containing numerous germ cells. The Müllerian ducts of control males had regressed, but this was prevented by oestrogen treatment, suggesting an inhibition of either Müllerian Inhibiting Substance (MIS) production or its action. Normal testicular migration was inhibited in treated males; the testes remained high in the abdomen, similar in position to the ovaries of control females, whilst control males all had testes in the inguinal region. The gubernaculum and processus vaginalis of control males extended into the scrotum, but in treated males they terminated outside it. Oestrogen treatment had no effect on the size of the scrotum and did not induce mammary or pouch development. These experiments show that marsupials, like eutherians, have a dual hormonal control of Wolffian and Müllerian development. By contrast, the initial development of the mammary glands, pouch, gubernaculum and scrotum does not appear to be under hormonal control and is therefore likely to be autonomous and dependent on genotype.
性发育的荷尔蒙控制。
影响因子：
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作者：
George,FW;Wilson,JD
通讯作者：
Wilson,JD