Rabahi F, Monniaux D, Pisselet C, Durand P
INRA, Station de Physiologie de la reproduction, URA CNRS, Nouzilly, Monnaie, France.
Mol Reprod Dev. 1993 Apr;34(4):431-42. doi: 10.1002/mrd.1080340413.
The present study was designed to investigate 1) the influence of the secretions of follicular cells on the in vitro maturation of bovine cumulus-oocyte complexes (COCs) and 2) the origin of the factors controlling the metabolic function of cumulus cells during the preovulatory period. Preovulatory granulosa cells were collected from synchronized heifers either before or 7-9 hr after the luteinizing hormone (LH) surge, and their secretions were recovered after a 3 hr incubation. Follicular fluids (FFs) originating from the same follicles and sera from the same animals were also collected. The effects of FFs, sera, and secretions of granulosa cells on COC metabolism were compared during 24 hr of culture. FF stimulated cumulus expansion, progesterone secretion, and overall protein synthesis by COCs but decreased the amount of a major protein of 28 kDa. The time at which FF was collected influenced both cumulus expansion and protein synthesis by COCs. The effects of FF on COC metabolism were detected at the lowest protein concentration studied (0.073 mg/ml) and could be mimicked with serum, but only at a protein concentration 100-fold higher. The inhibitory effect of FF and serum on the amount of the 28 kDa protein was reproduced with the secretions of granulosa cells, acting at protein concentrations five- and 500-fold lower, respectively. However, the secretions of granulosa cells enhanced slightly cumulus expansion and had no effect on progesterone secretion and overall protein synthesis by COCs. These results suggest that COC metabolism is influenced both by endocrine and by local factors secreted by granulosa cells in response to gonadotropins. The paracrine control of COC metabolism by preovulatory granulosa cells could be exerted not only via intercellular contacts but also via substances secreted in FF.
1）卵泡细胞分泌物对牛卵丘-卵母细胞复合体（COCs）体外成熟的影响；2）排卵前期控制卵丘细胞代谢功能的因子来源。从同期发情的小母牛中收集排卵前的颗粒细胞，分别在促黄体生成素（LH）峰出现之前或之后7-9小时采集，将其分泌物在孵育3小时后回收。同时收集来自相同卵泡的卵泡液（FFs）和相同动物的血清。在培养24小时期间，比较FFs、血清和颗粒细胞分泌物对COC代谢的影响。FF刺激COCs的卵丘扩展、孕酮分泌和总体蛋白质合成，但减少了一种主要的28 kDa蛋白质的量。收集FF的时间影响COCs的卵丘扩展和蛋白质合成。在研究的最低蛋白质浓度（0.073 mg/ml）下检测到FF对COC代谢的影响，血清在高100倍的蛋白质浓度下可模拟这种影响。FF和血清对28 kDa蛋白质含量的抑制作用可被颗粒细胞分泌物重现，其作用的蛋白质浓度分别低5倍和500倍。然而，颗粒细胞分泌物略微增强了卵丘扩展，对COCs的孕酮分泌和总体蛋白质合成没有影响。这些结果表明，COC代谢受内分泌和颗粒细胞响应促性腺激素分泌的局部因子的影响。排卵前颗粒细胞对COC代谢的旁分泌控制不仅可通过细胞间接触，还可通过FF中分泌的物质来实现。
