Expression of mRNA for the angiopoietin-Tie system in granulosa cells during follicular development in cows
Expression of mRNA for the angiopoietin-Tie system in granulosa cells during follicular development in cows
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DOI：
10.1262/jrd.50.477
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发表时间：
2004-08-01
影响因子：
1.8
通讯作者：
Miyamoto, A
中科院分区：
文献类型：
--
作者：
Hayashi, KG;Berisha, B;Miyamoto, A
最近的研究表明，血管生成素（ANPT）及其受体Tie 2的变化与周期性卵巢血管网络的发育和退化密切相关。我们以前报道，mRNA表达的ANPT-Tie系统在卵泡发育和闭锁牛卵泡内膜的变化，和两个ANPT影响排卵前卵泡的类固醇生成。本研究旨在探讨ANPT 1、ANPT-2和Tie 2在奶牛卵泡发育过程中颗粒细胞（GC）中的mRNA表达。根据卵泡液（FF）中雌二醇-17 β（E-2）浓度将牛卵泡分类如下：（1）E-2 < 0.5，（2）0.5 < E-2 < 5，（3）5 <E-2 < 20，（4）20 < E-2 < 180和（5）E-2 > 180 ng/ml FF。半定量RT-PCR分析显示，在E-2 < 5 ng/ml（直径5-10 mm）的卵泡中，绝大多数卵泡未检测到ANPT-1 mRNA的表达，而在E-2 > 5 ng/ml（直径> 10 mm）的卵泡中，ANPT-1 mRNA的表达均明显。当E-2 > 5 ng/ml时，ANPT-2 mRNA的表达显著降低。Tie 2 mRNA的表达在卵泡发育的不同阶段保持不变。目前的数据表明，ANPT-1成为主要的卵泡产生高水平的E-2，表明可能的转换从ANPT-2（拮抗剂）ANPT-1（激动剂）。因此，结果表明，ANPT-Tie系统在牛GC中可能刺激E-2分泌，而不是在卵泡发育的后期阶段的血管生成。
Recent findings indicate that the changing profile of angiopoietins (ANPT) and their receptor Tie2 are closely associated with development and regression of the vascular network in the cyclic ovary. We previously reported that mRNA expression for the ANPT-Tie system in theca interna changes during bovine follicular development and atresia, and both ANPTs affect steroidogenesis in the preovulatory follicle. The aim of this study was to investigate mRNA expression for ANPT1, ANPT-2 and Tie2 in granulosa cells (GC) during follicular development in the cow. Bovine follicles were classified according to the estradiol-17 beta (E-2) concentration in follicular fluid (FF) as follows: (1) E-2 < 0.5, (2) 0.5 < E-2 < 5, (3) 5 < E-2 < 20, (4) 20 < E-2 < 180 and (5) E-2 > 180 ng/ml FF. Semiquantitative RT-PCR analysis revealed that the expression of ANPT-1 mRNA was not detected in most of the follicle with E-2 < 5 ng/ml (diameter of 5-10 mm), but clearly detected in all follicles with E-2 > 5 ng/ml (diameter of > 10 mm). The mRNA expression for ANPT-2 was drastically decreased in the follicles with E-2 > 5 ng/ml. Tie2 mRNA expression remained unchanged at the different stages of follicular development. The present data show that ANPT-1 becomes predominant in the follicle producing high levels of E-2, indicating the possible switch-over from ANPT-2 (antagonist) to ANPT-1 (agonist). Thus, the result suggests that the ANPT-Tie system in bovine GC may stimulate E-2 secretion rather than angiogenesis in the late stages of follicular development.