George F W, Hodgins M B, Wilson J D
Endocrinology. 1985 Mar;116(3):1145-50. doi: 10.1210/endo-116-3-1145.
We have measured steroid hormone biosynthesis from pregnenolone in ovaries and testes, aromatization of testosterone in gonads and peripheral tissues, and 5 alpha-reduction of testosterone in peripheral tissues of developing opossum pouch young. Sex of the newborn opossums is discernible grossly with development of the pouch in females and the scrotum in males approximately 10 days after birth. Differentiated endocrine function of ovaries and testes was demonstrable as soon as development of the pouch or scrotum was apparent. The testes synthesized testosterone, and ovaries aromatized androgens to estrogens as assessed by the conversion of [1 beta-3H] testosterone to 3H2O. This endocrine differentiation of the gonads occurs days or weeks before differentiation of the male and female urogenital tracts. As in other species, 5 alpha-reduction of [1 beta-3H] testosterone was high in urogenital sinus and urogenital tubercle. However, 5 alpha-reductase activity was highest in mesonephros and structures derived from the mesonephros. In wolffian and mullerian ducts of pouch young less than 10 days old, 5 alpha-reductase activity was greater than 50 pmol/h . mg protein and decreased by 19 days of age to approximately 3 pmol/h . mg protein, a pattern different than in eutherian mammals in which testosterone itself appears to mediate virilization of the wolffian ducts. These studies provide the framework for studies of the endocrine control of phenotypic sexual differentiation in the opossum.
我们测定了发育中的负鼠育儿袋幼崽卵巢和睾丸中孕烯醇酮的类固醇激素生物合成、性腺和外周组织中睾酮的芳香化作用以及外周组织中睾酮的5α-还原作用。新生负鼠的性别在出生后约10天，随着雌性育儿袋和雄性阴囊的发育可通过肉眼辨别。一旦育儿袋或阴囊发育明显，卵巢和睾丸的内分泌功能分化就可显现。睾丸合成睾酮，而卵巢将雄激素芳香化为雌激素，这是通过[1β-3H]睾酮转化为3H2O来评估的。性腺的这种内分泌分化发生在雄性和雌性泌尿生殖道分化之前的数天或数周。与其他物种一样，泌尿生殖窦和泌尿生殖结节中[1β-3H]睾酮的5α-还原作用较高。然而，5α-还原酶活性在中肾及从中肾衍生的结构中最高。在小于10日龄的育儿袋幼崽的沃尔夫管和缪勒管中，5α-还原酶活性大于50 pmol/h·mg蛋白，到19日龄时降至约3 pmol/h·mg蛋白，这种模式与真兽类哺乳动物不同，在真兽类哺乳动物中，睾酮本身似乎介导沃尔夫管的雄性化。这些研究为负鼠表型性分化的内分泌控制研究提供了框架。
