Steroid contents of and steroidogenesis in vitro by the developing gonad and mesonephros around sexual differentiation in fetal sheep
Steroid contents of and steroidogenesis in vitro by the developing gonad and mesonephros around sexual differentiation in fetal sheep
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DOI：
10.1530/jrf.0.1140131
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发表时间：
1998-09-01
期刊：
影响因子：
--
通讯作者：
McNatty, KP
中科院分区：
文献类型：
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作者：
Lun, S;Smith, P;McNatty, KP
本研究的目的是建立是否类固醇，孕酮，雄烯二酮，睾酮和雌二醇，存在于雌性和雄性羊胎儿的中肾性腺复合体的性分化（即，从妊娠第28天至第45天，与性分化发生在大约第32天）。第二个目的是测试中肾-性腺复合体、中肾（仅第35-45天）和性腺（仅第35-45天）是否能够在体外合成类固醇。性分化前中肾-性腺复合体中未检测到类固醇激素含量。然而，从妊娠第35天起，中肾-卵巢复合体主要含有雌二醇，中肾-睾丸复合体主要含有睾酮：从第35天到第45天，这两种类固醇含量的增加超过了组织质量的增加五倍以上。从妊娠第40天至第45天，其他类固醇的含量在途径雌二醇逐步增加，在两种性别，但更多的平行组织质量的增加。相反，在恢复的组织中的类固醇含量，组织培养中的中肾性腺组织从两种性别能够合成大多数类固醇之前和之后的性分化，也代谢补充雄烯二酮雌二醇。这些发现表明，许多，如果不是全部，类固醇生成酶的途径，从胆固醇雌二醇是目前性别分化之前。大多数上述类固醇存在于可检测到的量在分离的中肾和性腺的性别分化后。此外，对于两个孤立的中肾和性腺，有增加的平均含量的大多数类固醇培养后相对于在恢复组织中的内容。这些数据表明，中肾，以及性腺，在两种性别是能够合成类固醇。它的结论是，在羊胎儿，女性和男性性腺的类固醇激素活性后，性分化，类固醇激素生成酶的发展之前，性分化，和中肾是类固醇合成的网站。
The aim of the present study was to establish whether the steroids, progesterone, androstenedione, testosterone and oestradiol, were present in the mesonephricgonadal complex of female and male sheep fetuses around sexual differentiation (that is, from day 28 to day 45 of gestation, with sexual differentiation occurring at approximately day 32). A second aim was to test whether the mesonephric-gonadal complex, mesonephros (days 35-45 only) and gonad (days 35-45 only) were capable of steroid synthesis in vitro. The steroid contents in the mesonephric-gonadal complex were not detectable before sexual differentiation. However, from day 35 of gestation onwards, the mesonephric-ovarian complex contained mainly oestradiol and the mesonephric-testicular complex contained mainly testosterone: from day 35 until day 45 the increase in content of these two steroids exceeded the increase in the mass of tissue by more than fivefold. From day 40 to day 45 of gestation, the contents of the other steroids in the pathways to oestradiol increased progressively in both sexes but more in parallel with the increase in tissue mass. In contrast to the steroid contents in the tissue at recovery, the mesonephric-gonadal tissue from both sexes in tissue culture was able to synthesize most steroids before and after sexual differentiation and also to metabolise supplementary androstenedione to oestradiol. These findings suggest that many, if not all, of the steroidogenic enzymes in the pathway from cholesterol to oestradiol are present before sexual differentiation. Most of the aforementioned steroids were present in detectable amounts in isolated mesonephros and gonad of both sexes after sexual differentiation. Moreover, for both the isolated mesonephros and gonad, there were increases in the mean contents of most steroids after culture relative to the contents in the tissues at recovery. These data suggest that the mesonephros, as well as the gonad, in both sexes is capable of synthesizing steroid. It is concluded that, in the sheep fetus, the female and male gonads are steroidogenically active after sexual differentiation, that the steroidogenic enzymes develop before sexual differentiation, and that the mesonephros is a site of steroid synthesis.