Yoshida K, Shimada K, Saito N
Laboratory of Animal Physiology, School of Agricultural Sciences, Nagoya University, Nagoya, Japan.
Gen Comp Endocrinol. 1996 May;102(2):233-40. doi: 10.1006/gcen.1996.0064.
The onset and localization of P450(17-alpha)-hydroxylase (P450(17-alpha)) and P450 aromatase (P450arom) mRNA expression were studied in the gonads of chicken embryos at Days 4-9 of incubation by in situ hybridization analysis, and expression of both mRNAs was measured in the ovary and testis of the chicken after sexual differentiation by Northern and slot-blot analysis and was related to changes in concentration of 17-beta-estradiol (E2) in the gonad. In situ hybridization analysis showed the first detection of P450(17-alpha) mRNA at Days 5-6 of incubation in the genetic male and female gonads and the first detection of P450arom at Day 6.5 of incubation in the female gonad but none was detected in the male gonad. Both mRNAs were observed in the medullary cords of the gonad. Slot-blot analysis demonstrated that levels of P450(17-alpha) mRNA in the ovary remained high during the period between Day 10 of incubation and 7 days of posthatching, while those in the testis remained low at Days 10-14 of incubation but increased at Day 16 of incubation up to posthatching days. Levels of P450arom mRNA in the left ovary were invariably higher than those of the right ovary and testis throughout the period between Day 10 of incubation and 7 days of posthatching. These results suggest that expression of P450arom mRNA occurring in the genetic female gonad around Day 6 is associated, at least in a part, with sexual differentiation toward femaleness by increasing E2 production which may promote cellular proliferation of the left gonad. In contrast, in the genetic male gonad marked expression of P450(17-alpha) mRNA with little expression of P450arom mRNA may lead to production of androgen which promotes the gonadal development to the testis.
通过原位杂交分析研究了孵化第4至9天鸡胚性腺中P450(17-α)-羟化酶（P450(17-α)）和P450芳香化酶（P450arom）mRNA表达的起始和定位，并通过Northern和狭缝印迹分析测定了性别分化后鸡卵巢和睾丸中这两种mRNA的表达，并将其与性腺中17-β-雌二醇（E2）浓度的变化相关联。原位杂交分析显示，在遗传型雄性和雌性性腺中，孵化第5至6天首次检测到P450(17-α) mRNA，在雌性性腺中，孵化第6.5天首次检测到P450arom mRNA，但在雄性性腺中未检测到。在性腺的髓索中观察到这两种mRNA。狭缝印迹分析表明，孵化第10天至出壳后7天期间，卵巢中P450(17-α) mRNA水平保持较高，而在孵化第10至14天睾丸中的水平较低，但在孵化第16天至出壳后有所增加。在孵化第10天至出壳后7天的整个期间，左卵巢中P450arom mRNA水平始终高于右卵巢和睾丸。这些结果表明，孵化第6天左右在遗传型雌性性腺中出现的P450arom mRNA表达，至少部分与向雌性的性别分化有关，并通过增加E2的产生来促进左性腺的细胞增殖。相反，在遗传型雄性性腺中，P450(17-α) mRNA的显著表达和P450arom mRNA的少量表达可能导致雄激素的产生，从而促进性腺向睾丸发育。
