Luderer Ulrike, Diaz Dolores, Faustman Elaine M, Kavanagh Terrance J
Department of Medicine, Division of Occupational and Environmental Medicine, University of California, Irvine, California 96212, USA.
Mol Reprod Dev. 2003 Jul;65(3):254-61. doi: 10.1002/mrd.10298.
Ovarian levels of the antioxidant tripeptide glutathione (GSH) increase following gonadotropin administration, suggesting that GSH synthesis in the ovary may be associated with follicular growth. In situ hybridization with (35)S-labeled riboprobes was used to localize ovarian mRNA expression of the catalytic and modulatory subunits of glutamate cysteine ligase (Gclc and Gclm), the rate-limiting enzyme in GSH synthesis, during each stage of the rat estrous cycle. Gclm was highly expressed in the granulosa cells and oocytes of healthy, growing follicles, not in atretic follicles. Gclc was also highly expressed in follicles; however, unlike Gclm, Gclc was also expressed in corpora lutea and interstitial cells. In a subsequent experiment, the hypothesis that GSH synthesis occurs in healthy, but not in apoptotic, follicles was tested. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) was used to detect apoptotic cells in the ovaries, and in situ hybridization for Gclm and Gclc was performed in adjacent sections of the same ovaries. TUNEL staining was found to be significantly associated with absence of Gclm hybridization in granulosa cells and oocytes and with lack of strong Gclc hybridization in granulosa cells. These results suggest that follicular apoptosis may be associated with down-regulation of Gclm and Gclc transcription in granulosa cells and oocytes.
促性腺激素给药后，卵巢中抗氧化三肽谷胱甘肽（GSH）水平升高，这表明卵巢中GSH的合成可能与卵泡生长有关。在大鼠动情周期的每个阶段，使用与（35）S标记的核糖探针进行原位杂交，以定位谷胱甘肽合成的限速酶谷氨酸半胱氨酸连接酶（Gclc和Gclm）的催化和调节亚基在卵巢中的mRNA表达。Gclm在健康的生长卵泡的颗粒细胞和卵母细胞中高表达，而在闭锁卵泡中不表达。Gclc在卵泡中也高表达；然而，与Gclm不同，Gclc在黄体和间质细胞中也有表达。在随后的实验中，对GSH合成发生在健康卵泡而非凋亡卵泡中的假设进行了测试。使用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）检测卵巢中的凋亡细胞，并在同一卵巢的相邻切片中进行Gclm和Gclc的原位杂交。发现TUNEL染色与颗粒细胞和卵母细胞中Gclm杂交的缺失以及颗粒细胞中缺乏强烈的Gclc杂交显著相关。这些结果表明，卵泡凋亡可能与颗粒细胞和卵母细胞中Gclm和Gclc转录的下调有关。
