College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China.
Key Laboratory of Animal Bio-Technology, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China.
Int J Biol Sci. 2019 Jan 1;15(2):404-415. doi: 10.7150/ijbs.27912. eCollection 2019.
Melatonin is present in mammalian follicular fluid and plays an important role in regulating steroidogenesis in follicular cells. In this study, we report the effect of melatonin on steroidogenesis in the theca interna (TI) in small bovine follicles and theca cells (TCs) cultured in vitro. Treatment with melatonin significantly increased the expression of steroidogenic acute regulatory protein (STAR) and the production of progesterone in both TI and in TCs. Melatonin stimulated the phosphorylation of AKT but not ERK1/2, and the addition of luzindole (a nonspecific MT1 and MT2 inhibitor) or 4P-PDOT (specific MT2 inhibitor) reduced melatonin-induced STAR expression, progesterone secretion, and PI3K/AKT pathway activation. The effect of melatonin on the TI in follicles was more obvious than on the TCs in vitro. Results indicate that melatonin stimulates the steroidogenesis of TCs mainly via the activation of the PI3K/AKT pathway by MT1 and MT2.
褪黑素存在于哺乳动物的卵泡液中，在调节卵泡细胞中的类固醇生成中起着重要作用。在这项研究中，我们报告了褪黑素对小牛卵泡中的膜内层（TI）和体外培养的膜细胞（TCs）中的类固醇生成的影响。褪黑素处理显著增加了类固醇急性调节蛋白（STAR）的表达和 TI 和 TCs 中孕酮的产生。褪黑素刺激 AKT 的磷酸化，但不刺激 ERK1/2 的磷酸化，而 luzindole（非特异性 MT1 和 MT2 抑制剂）或 4P-PDOT（特异性 MT2 抑制剂）的添加则降低了褪黑素诱导的 STAR 表达、孕酮分泌和 PI3K/AKT 途径的激活。褪黑素对卵泡 TI 的作用比体外对 TCs 的作用更明显。结果表明，褪黑素主要通过 MT1 和 MT2 激活 PI3K/AKT 通路来刺激 TCs 的类固醇生成。
