Interaction among beta-endorphin, nitric oxide and prostaglandins during ovulation in rats
Interaction among beta-endorphin, nitric oxide and prostaglandins during ovulation in rats
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DOI：
10.1530/reprod/125.4.469
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发表时间：
2003-04-01
期刊：
影响因子：
3.8
通讯作者：
Rettori, V
中科院分区：
文献类型：
--
作者：
Faletti, AG;Mohn, C;Rettori, V
本研究旨在探讨大鼠排卵过程中β-内啡肽与一氧化氮（NO）的关系。用马绒毛膜促性腺激素-hCG处理未成熟大鼠以诱导排卵。囊内注射β-内啡肽刺激一氧化氮合酶（NOS）活性。当纳洛酮与β-内啡肽共同注射时，这种作用完全逆转。研究了β-内啡肽对NOS活性的刺激作用，以确定其是否通过洋地黄素发挥作用。用前列腺素E-2（PGE（2））处理完全逆转了β-内啡肽诱导的NOS活性刺激。此外，囊内注射美洛昔康，环氧化酶2的抑制剂，增加NOS活性，但这种效果没有改变共同注射β-内啡肽。用免疫印迹法检测hCG处理后10 h卵巢中内皮型一氧化氮合酶（eNOS）和诱导型一氧化氮合酶（iNOS）的表达。局部应用β-内啡肽可抑制eNOS蛋白的表达，而未检测到iNOS蛋白的表达。注射hCG后10 h卵巢β-内啡肽含量减少。体内前列腺素合成抑制剂治疗增加了卵巢β-内啡肽含量。总之，这些结果表明β-内啡肽通过抑制前列腺素的产生间接刺激卵巢NOS的活性。
The aim of this study was to investigate the relationship between beta-endorphin and nitric oxide (NO) during the ovulatory process in rats. Immature rats were treated with equine chorionic gonadotrophin-hCG to induce ovulation. An intrabursal injection of beta-endorphin stimulated nitric oxide synthase (NOS) activity. This effect was completely reversed when naltrexone was co-injected with beta-endorphin. The stimulatory action of beta-endorphin on NOS activity was studied to determine whether it was exerted via prostaglandins. Treatment with prostaglandin E-2 (PGE(2)) completely reversed the beta-endorphin-induced stimulation of NOS activity. Moreover, intrabursal injection of meloxicam, an inhibitor of cyclooxygenase 2, increased NOS activity, but this effect was not altered by co-injection with beta-endorphin. The presence of both endothelial NOS (eNOS) and inducible NOS (iNOS) in the ovary at 10 h after hCG treatment was studied by western blot analysis. Local administration of beta-endorphin inhibited the expression of eNOS protein, whereas expression of iNOS protein was not detectable. Ovarian beta-endorphin content was diminished at 10 h after hCG injection. Treatment with prostaglandin synthesis inhibitors in vivo augmented the ovarian beta-endorphin content. In conclusion, these results indicate that beta-endorphin stimulates the activity of ovarian NOS indirectly by inhibiting prostaglandin production.