Blyth B, Duckett J W
Division of Urology, Children's Hospital of Philadelphia, Pennsylvania.
J Urol. 1991 Apr;145(4):689-94. doi: 10.1016/s0022-5347(17)38426-4.
The sexual differentiation of a gonad is determined in normal embryology by the presence or absence of the TDF gene, a short segment of DNA localized near the tip of the short arm of the Y chromosome. Under the stimulus of this gene, the somatic cells of the genital ridge differentiate into Sertoli cells and secrete anti-müllerian hormone. This hormone inhibits the germ cells from entering meiosis and may well also trigger the formation of the primary sex cords. Once the Sertoli cells are formed, further differentiation of the gonad is independent of the TDF presence, although this gene may further contribute to the normal functioning of the male gonad. In true hermaphroditism the normal regulation of the gonadal differentiation is missing. Gonadal differentiation may revert to a more primitive evolutionary level at which the rate of growth of the gonad determines its sexual direction. When this exceeds a certain threshold a testis may develop despite the absence of the TDF gene.
在正常胚胎学中，性腺的性别分化由TDF基因的存在与否决定，TDF基因是一段位于Y染色体短臂末端附近的短DNA片段。在该基因的刺激下，生殖嵴的体细胞分化为支持细胞并分泌抗苗勒管激素。这种激素抑制生殖细胞进入减数分裂，也很可能触发初级性索的形成。一旦支持细胞形成，性腺的进一步分化就独立于TDF基因的存在，尽管该基因可能进一步有助于男性性腺的正常功能。在真两性畸形中，性腺分化的正常调节缺失。性腺分化可能会恢复到一个更原始的进化水平，在这个水平上，性腺的生长速度决定其性别方向。当生长速度超过某个阈值时，即使没有TDF基因，也可能发育出睾丸。
