Department of Animal Science, Shandong Agricultural University, Taian, Shandong 271018, People's Republic of China.
J Lipid Res. 2013 Jul;54(7):1860-76. doi: 10.1194/jlr.M036301. Epub 2013 Apr 18.
Glucocorticoids participate in the arousal of stress responses and trigger physiological adjustments that shift energy away from reproduction toward survival. Ovarian follicular development in avians is accompanied by the supply of yolk precursors, which are mainly synthesized in the liver. Therefore, we hypothesized energy status and hepatic lipogenesis are involved in the induction of reproductive disorders by glucocorticoids in laying hens. The results show that corticosterone decreased the laying performance by suppressing follicular development in energy-deficit state, rather than in energy-sufficient state. In corticosterone-treated hens, the suppressed follicular development was associated with the reduced availability of yolk precursor, indicated by the plasma concentration of VLDL and vitellogenin and the decreased proportion of yolk-targeted VLDL (VLDLy). Corticosterone decreased the expression of apolipoprotein B and apolipoprotein VLDL-II in the liver. A drop in VLDL receptor content and an increase in the expression of tight junction proteins occludin and claudin1 were also observed in hierarchical follicles. The results suggest corticosterone-suppressed follicular development is energy dependent. The decreased apolipoprotein synthesis and VLDLy secretion by liver are responsible for the decreased availability of circulating yolk precursor, and the upregulation of occludin and claudin expression further prevents yolk deposition into oocytes.
糖皮质激素参与应激反应的唤醒，并引发生理调整，将能量从生殖转移到生存。禽类的卵巢卵泡发育伴随着卵黄前体的供应，这些卵黄前体主要在肝脏中合成。因此，我们假设能量状态和肝脂生成参与了糖皮质激素在产蛋母鸡中诱导生殖障碍的过程。结果表明，皮质酮在能量不足状态下通过抑制卵泡发育来降低产蛋性能，而不是在能量充足状态下。在皮质酮处理的母鸡中，卵泡发育受到抑制与卵黄前体的可用性降低有关，这表现为血浆 VLDL 和卵黄蛋白浓度以及卵黄靶向 VLDL（VLDLy）的比例降低。皮质酮降低了肝脏中载脂蛋白 B 和载脂蛋白 VLDL-II 的表达。在分级卵泡中还观察到 VLDL 受体含量下降和紧密连接蛋白 occludin 和 claudin1 的表达增加。这些结果表明，皮质酮抑制卵泡发育是依赖能量的。肝脏中载脂蛋白合成和 VLDLy 分泌减少导致循环卵黄前体的可用性降低，occludin 和 claudin 表达的上调进一步阻止卵黄沉积到卵母细胞中。
