MULTIPLE STEROIDOGENIC CELL-POPULATIONS IN THE THECAL LAYER OF PREOVULATORY FOLLICLES OF THE CHICKEN OVARY
MULTIPLE STEROIDOGENIC CELL-POPULATIONS IN THE THECAL LAYER OF PREOVULATORY FOLLICLES OF THE CHICKEN OVARY
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DOI：
10.1210/endo-129-4-2033
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发表时间：
1991-10-01
期刊：
影响因子：
4.8
通讯作者：
BAHR, JM
中科院分区：
文献类型：
--
作者：
NITTA, H;OSAWA, Y;BAHR, JM
鸡卵巢排卵前卵泡的膜层主要产生雄激素和雌激素。然而，鞘层中雄激素和雌激素合成的精确细胞位点尚未确定。因此，我们的目标是1）通过免疫细胞化学定位这些细胞中的特定类固醇生成酶来鉴定排卵前卵泡膜层中的类固醇生成细胞，2）确认这些含有特定类固醇生成酶的细胞在短期细胞孵育中分泌预期的类固醇。产卵后2小时收集卵泡并准备用于免疫细胞化学和短期细胞孵育。对胆固醇侧链裂解细胞色素 P450 (P450SCC)、17-α-羟化酶细胞色素 P450 (P450C17) 和芳香酶细胞色素 P450 (P450AROM) 进行免疫细胞化学，以分别在五个最大排卵前的冰冻切片和石蜡切片上定位孕烯醇酮、雄激素和雌激素产生细胞。毛囊。间质细胞显示出对 P450SCC 和 P450C17 的免疫反应性，而外部膜的特定细胞群（以下称为芳香酶细胞）显示出对 P450AROM 的免疫反应性。此外，外部卵泡膜中的成纤维细胞显示出对 P450C17 的免疫反应性。外膜层特定细胞中P450C17和P450AROM酶的免疫反应性似乎随着卵泡的成熟而降低。选择第三大、第四大和第五大卵泡进行短期细胞培养，因为这些卵泡膜层中P450酶的免疫反应性较高。分离的卵泡膜内部细胞、卵泡膜外部细胞以及内部和外部细胞的组合在有/没有绵羊LH (oLH)的情况下孵育3小时。通过 RIA 测定培养基中的孕酮、睾酮和 17-β-雌二醇。卵泡膜内细胞与 oLH 一起孵育以剂量依赖性方式增加孕酮和睾酮的产生。然而，我们没有观察到外部卵泡膜细胞产生任何孕酮和睾酮。外膜细胞产生 17-β-雌二醇，并且当内膜细胞和外膜细胞在 oLH 存在下共孵育时，其产量显着增加。基于这些数据，我们提出了鸡卵巢排卵前卵泡膜层中类固醇生成的多细胞理论，该理论指出，内膜中的间质细胞产生孕激素和雄激素，外膜中的成纤维细胞可能发挥作用作为孕激素转化为雄激素的附加位点，外部卵泡膜中的芳香酶细胞需要雄激素作为底物来产生雌激素。
The thecal layer of the preovulatory follicle of the chicken ovary produces primarily androgens and estrogens. However, the precise cellular sites of androgen and estrogen synthesis in the thecal layer have not been identified. Therefore, our aims were 1) to identify steroidogenic cells in the thecal layer of the preovulatory follicles by localizing specific steroidogenic enzymes in these cells by immunocytochemistry, and 2) to confirm that these cells which contained the specific steroidogenic enzymes secreted the expected steroid in a short term cell incubation.Follicles were collected 2 h after oviposition and prepared for immunocytochemistry and short term cell incubation. Immunocytochemistry for cholesterol side-chain cleavage cytochrome P450 (P450SCC), 17-alpha-hydroxylase cytochrome P450 (P450C17), and aromatase cytochrome P450 (P450AROM) was performed to localize pregnenolone-, androgen-, and estrogen-producing cells, respectively, on frozen sections and paraffin sections of the five largest preovulatory follicles. Interstitial cells showed immunoreactivity for both P450SCC and P450C17, whereas a specific cell population of the theca externa, hereafter termed aromatase cells, showed immunoreactivity for P450AROM. Furthermore, fibroblasts in the theca externa indicated immunoreactivity for P450C17. The immunoreactivity of P450C17 and P450AROM enzymes in specific cells in the theca externa appeared to decrease with follicular maturation.The third largest, fourth largest, and fifth largest follicles were selected for short term cell incubations because the immunoreactiviy for P450 enzymes in the thecal layer of these follicles was high. Isolated theca interna cells, theca externa cells, and a combination of interna and externa cells were incubated with/without ovine LH (oLH) for 3 h. The medium was assayed for progesterone, testosterone, and 17-beta-estradiol by RIAs. Incubation of theca interna cells with oLH increased progesterone and testosterone production in a dose-dependent manner. However, we did not observe any production of progesterone and testosterone by theca externa cells. Theca externa cells produced 17-beta-estradiol, and its production was increased significantly when theca interna and externa cells were coincubated in the present of oLH.Based on these data, we propose a multiple cell theory for steroidogenesis in the thecal layer of preovulatory follicles of the chicken ovary which states that interstitial cells in the theca interna produce progestins and androgens, fibroblasts in the theca externa may function as an additional site for the conversion of progestins to androgens, and aromatase cells in the theca externa require androgens as substrate to produce estrogens.