Neuvians T P, Pfaffl M W, Berisha B, Schams D
Institute of Physiology, Technical University Munich, Weihenstephaner Berg 3, Freising-Weihenstephan D-85350, Germany.
Domest Anim Endocrinol. 2003 Nov;25(4):359-72. doi: 10.1016/j.domaniend.2003.08.002.
The components of the IGF-system were shown to be differentially regulated in bovine antral follicles and corpora lutea (CL) during different stages of the estrous cycle, and to have important functions for specific stages. The aim of this study was to investigate the detailed pattern of mRNA expression of most constituents of the IGF-system and their possible involvement in prostaglandin (PG)F2alpha-induced luteolysis in the bovine CL. Therefore, cows in the mid-luteal phase (days 8-12) were injected with the PGF2alpha-analogue Cloprostenol, and CL were collected by transvaginal ovariectomy at 2, 4, 12, 48 and 64 h after PGF2alpha-injection. Real-time RT-PCR using SYBR Green I detection was employed to determine mRNA expressions of the following factors: ubiquitin (UBQ), insulin-like growth factor I (IGF I), IGF II, IGF-receptor type 1 (IGFR-1), growth hormone receptor (GH-R) and IGF-binding proteins-1-6 (IGFBP-1-6). Total extractable RNA decreased with ongoing luteolysis. IGFBP-1 mRNA was significantly up-regulated at 2h after PGF2alpha and maximal at 4h with a 34-fold increase. IGFBP-5 mRNA was significantly up-regulated after 12h with a maximum of an 11-fold increase at 64 h. For GH-R, IGFR-1, IGF II, IGFBP-3 and -4 mRNA expression, we found a significant down-regulation in certain stages. There was a significant up-regulation for IGFBP-2 and -6 mRNA at 64 h after induced luteolysis. There were no significant changes in IGF I mRNA expression. In conclusion, the IGF-system with all its components seems to play an important role in the very complex process of PGF2alpha-induced luteolysis in bovine CL.
研究表明，在发情周期的不同阶段，胰岛素样生长因子（IGF）系统的各组分在牛的窦状卵泡和黄体（CL）中受到不同调控，并在特定阶段发挥重要作用。本研究旨在探究IGF系统大多数组分的mRNA表达详细模式，以及它们在牛黄体中前列腺素（PG）F2α诱导的黄体溶解过程中可能发挥的作用。因此，对处于黄体中期（第8 - 12天）的母牛注射PGF2α类似物氯前列醇，并在注射PGF2α后2、4、12、48和64小时通过经阴道卵巢切除术采集黄体。采用SYBR Green I检测的实时逆转录聚合酶链反应（RT-PCR）来测定以下因子的mRNA表达：泛素（UBQ）、胰岛素样生长因子I（IGF I）、IGF II、1型IGF受体（IGFR-1）、生长激素受体（GH-R）以及IGF结合蛋白-1 - 6（IGFBP-1 - 6）。随着黄体溶解的进行，总可提取RNA减少。PGF2α注射后2小时，IGFBP-1 mRNA显著上调，4小时达到最大值，增加了34倍。12小时后IGFBP-5 mRNA显著上调，64小时达到最大值，增加了11倍。对于GH-R、IGFR-1、IGF II、IGFBP-3和-4 mRNA表达，我们发现在某些阶段显著下调。诱导黄体溶解后64小时，IGFBP-2和-6 mRNA显著上调。IGF I mRNA表达无显著变化。总之，IGF系统及其所有组分似乎在牛黄体中PGF2α诱导的非常复杂的黄体溶解过程中发挥重要作用。
