Porter T E, Hargis B M, Silsby J L, el Halawani M E
Department of Animal Science, University of Minnesota, Saint Paul 55108.
Endocrinology. 1989 Jul;125(1):109-16. doi: 10.1210/endo-125-1-109.
In avian species, the granulosa cells produce progesterone (P), but not testosterone (T) or estradiol (E). The theca folliculi in avian species produces T and E and is anatomically comprised of the theca interna and the theca externa. It is not known, however, whether both T and E are produced by the same cell type. In the present study, preovulatory follicles of adult female turkeys were separated into their anatomical subdivisions, the granulosa, theca interna, and theca externa, and the relative steroidogenic contribution by each layer was investigated. Granulosa cells from the largest (F1) and fifth largest (F5) preovulatory follicles produced increasing levels of P in response to ovine LH (oLH; 0-10 micrograms/ml); however, T and E were not detectable. Theca interna and theca externa cells from F5 follicles were cultured alone or in combination. Theca interna cells produced P and T, but not E. Theca externa cells produced P, T, and E. E production was greatly enhanced by coincubation of cells from the two theca layers. oLH, (0-100 ng/ml) stimulated theca interna P and T production and E production by the coincubation of theca interna and theca externa cells. When theca interna and theca externa cells from the F1 and F5 follicles were tested, theca externa cells from F5, but not F1, converted androstenedione and T, but not P into E, indicating a loss of aromatase activity in the theca externa with follicular maturation. Neither F1 nor F5 theca interna cells converted P, A, or T into estradiol, providing additional evidence that aromatase activity is limited exclusively to the theca externa. Addition of oLH (0-100 ng/ml) did not increase conversion of T into E by the F5 theca externa cells, suggesting that production of E by the theca externa is substrate driven and not influenced by direct LH action. Avian ovarian steroidogenesis is described using a three-cell model, with the principle sources of P, T, and E being the granulosa, theca interna, and theca externa cells, respectively.
在鸟类中，颗粒细胞产生孕酮（P），但不产生睾酮（T）或雌二醇（E）。鸟类的卵泡膜由内膜和外膜组成，能产生T和E。然而，尚不清楚T和E是否由同一细胞类型产生。在本研究中，将成年雌性火鸡的排卵前卵泡分离为颗粒层、内膜和外膜等解剖亚结构，并研究了各层相对的类固醇生成作用。来自最大（F1）和第五大（F5）排卵前卵泡的颗粒细胞，对羊促黄体生成素（oLH；0 - 10微克/毫升）的反应是产生水平不断升高的P；然而，未检测到T和E。单独或联合培养F5卵泡的内膜细胞和外膜细胞。内膜细胞产生P和T，但不产生E。外膜细胞产生P、T和E。两层卵泡膜细胞共同培养可大大增强E的产生。oLH（0 - 100纳克/毫升）刺激内膜细胞产生P和T，并通过内膜细胞与外膜细胞共同培养刺激E的产生。当检测F1和F5卵泡的内膜细胞和外膜细胞时，F5而非F1的外膜细胞将雄烯二酮和T而非P转化为E，这表明随着卵泡成熟，外膜细胞中的芳香化酶活性丧失。F1和F5的内膜细胞均未将P、雄烯二酮（A）或T转化为雌二醇，这进一步证明芳香化酶活性仅局限于外膜。添加oLH（0 - 100纳克/毫升）并未增加F5外膜细胞将T转化为E的能力，这表明外膜产生E是由底物驱动的，不受LH直接作用的影响。鸟类卵巢类固醇生成采用三细胞模型描述，P、T和E的主要来源分别是颗粒细胞、内膜细胞和外膜细胞。
