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Regulation mechanisms of transcription of sex steroidogenic enzymes during follicular growth in the chicken.

鸡卵泡生长过程中性类固醇生成酶转录的调节机制。

基本信息

批准号：
04454106
负责人：
SHIMADA Kiyoshi
金额：
$ 3.01万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

项目摘要

Concentrations of estradiol (E), testosterone (T) and progesterone (P), and levels of the 1.9-kb and 4.0-kb mRNA encoding P450_<17alpha> hydroxylase(P450_<17alpha>) and P450_<aromatase> (P450_<arom>), respectively, were measured in the isolated granulosa, theca interna and theca externa of the largest preovulatory (F1-F4) follicles of the chicken 20 h and 3 h before expected ovulation of F1. In the granulosa layr, E and T concentrations remained low throughout this period of follicular growth, whereas P concentrations were high 3 h before ovulation in F2 and F1 follicles. Estradiol levels were highest in the theca interna and externa of the amallest (F4) follicle, decreasing progressively with follicular growth. Testosterone content of theca interna and granulosa was greater in less mature F4-F2 follicles than that found in the most mature (F1) follicle, whereas theca externa contained little T.P was quantifiable in significant amounts only in granulosa tissue, peaking in F2 and F1 follicles at 3 h before ovulation, at which time plasma levels of steroids also rose significantly. P450_<17alpha> was expressed mainly in theca interna, whereas P450_<arom> mRNA levels found in theca externa refiected the pattern of E in this compartment. Expression of these two genes was very low in granulosa tissue, remaining unchanged during follicular growth. These results indicate that E and T synthesis in the chicken ovary is regulated, at least in part, at mRNA levels of P450_<17alpha> and P450_<arom> in the theca interna and theca externa layrs during follicular growth.

测定了鸡最大排卵前期(F1-F4)卵泡在预期排卵前20h和3h的颗粒、内膜和外膜中雌二醇(E)、睾酮(T)和孕酮(P)的浓度，以及编码P450和P450芳香酶的1.9kb和4.0kb羟基酶(P450)和芳香酶(P450)的水平。在颗粒卵泡层中，E和T浓度在整个卵泡生长期内保持在低水平，而在F2和F1卵泡中，P浓度在排卵前3h处于较高水平。最大(F4)卵泡的内膜和外膜雌二醇水平最高，随着卵泡的生长逐渐降低。未成熟的F4-F2卵泡内膜和颗粒的睾酮含量高于最成熟的(F1)卵泡，而外膜的睾酮含量较低，仅在颗粒组织中有显著含量，F2和F1卵泡在排卵前3h达到峰值，此时血浆类固醇水平也显著升高。P450_lt；17α&gt；主要在内膜表达，而外膜中P450_lt；arom&gt；mRNA的表达反映了E在该隔室的分布模式。这两个基因在颗粒组织中的表达很低，在卵泡生长过程中保持不变。这些结果表明，鸡卵巢中E和T的合成在卵泡发育过程中至少部分地受到内膜和外膜P450_lt；17pha&gt；和P450_lt；arom&gt；mRNA水平的调节。