Jannini E A, Ulisse S, Cecconi S, Cironi L, Colonna R, D'Armiento M, Santoni A, Cifone M G
Department of Experimental Medicine, University of L'Aquila, Italy.
Biol Reprod. 1994 Jul;51(1):140-5. doi: 10.1095/biolreprod51.1.140.
The possibility that FSH stimulates the phospholipase A2 (PLA2) pathway was studied in cultured immature Sertoli cells. FSH induced [3H]-arachidonic acid (AA) release from prelabeled cells in a time- and concentration-dependent fashion (ED50 = 21.8 +/- 1.9 ng/ml). This response could be fully prevented by pretreatment of cells with the PLA2 inhibitor, mepacrine. That PLA2 was the main enzyme responsible for cleavage of AA from membrane phospholipids was directly shown by PLA2 activity assay using vesicles of radiolabeled phosphatidylcholine (PC) as substrate. Furthermore, FSH stimulated eicosanoid generation in a time-dependent manner through the cyclooxygenase but not the lipoxygenase pathway. In fact, higher levels of prostaglandin (PG) E2, F2 alpha, and the stable products of PGI2 and thromboxane A2 (6-keto PGF1 alpha and thromboxane B2, respectively) were generated by the gonadotropin-treated cells as compared to control cells. The effect was inhibited by mepacrine, further supporting the pivotal role of PLA2 in the release of the eicosanoid precursor, AA. Finally, the effect of the main product of FSH-induced AA metabolism, i.e., PGE2, was studied. Intracellular cAMP accumulation in Sertoli cells was stimulated by the prostanoid in a dose-dependent manner (ED50 = 2.3 +/- 0.37 nM). PGE2 also significantly stimulated aromatase activity, a specific marker of Sertoli cell functions, measured as 17 beta-estradiol production (ED50 = 4.7 +/- 0.8 nM). Similar results were obtained with PGF2 alpha. Our findings show that FSH, through the activation of PLA2, leads to AA release with consequent metabolism by the cyclooxygenase pathway.(ABSTRACT TRUNCATED AT 250 WORDS)
在培养的未成熟支持细胞中研究了促卵泡激素（FSH）刺激磷脂酶A2（PLA2）途径的可能性。FSH以时间和浓度依赖性方式诱导预标记细胞释放[3H] - 花生四烯酸（AA）（半数有效剂量[ED50] = 21.8±1.9 ng/ml）。用PLA2抑制剂米帕林预处理细胞可完全阻止这种反应。使用放射性标记的磷脂酰胆碱（PC）囊泡作为底物的PLA2活性测定直接表明PLA2是负责从膜磷脂中裂解AA的主要酶。此外，FSH通过环氧化酶途径而非脂氧合酶途径以时间依赖性方式刺激类花生酸生成。事实上，与对照细胞相比，促性腺激素处理的细胞产生了更高水平的前列腺素（PG）E2、F2α以及PGI2和血栓素A2的稳定产物（分别为6 - 酮 - PGF1α和血栓素B2）。米帕林抑制了这种作用，进一步支持了PLA2在类花生酸前体AA释放中的关键作用。最后，研究了FSH诱导的AA代谢的主要产物即PGE2的作用。前列腺素以剂量依赖性方式刺激支持细胞内cAMP积累（ED50 = 2.3±0.37 nM）。PGE2还显著刺激芳香化酶活性，这是支持细胞功能的特异性标志物，以17β - 雌二醇生成量来衡量（ED50 = 4.7±0.8 nM）。用PGF2α获得了类似结果。我们的研究结果表明，FSH通过激活PLA2导致AA释放，随后通过环氧化酶途径进行代谢。（摘要截断于250字）
