Mercure F, Van Der Kraak G
Department of Zoology, University of Guelph, Ontario, Canada.
Lipids. 1995 Jun;30(6):547-54. doi: 10.1007/BF02537030.
The effects of the polyunsaturated fatty acids (PUFAs)--eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA)--on in vitro steroid production by full-grown prematurational ovarian follicles from goldfish and rainbow trout were investigated. EPA and DHA inhibited gonadotropin-stimulated testosterone production in a dose-related manner, but AA was inhibitory only at the highest dose tested (400 microM). AA alone stimulated testosterone production by increasing cAMP production, but the effects of other PUFAs alone were marginal. The inhibitory actions by PUFAs were not restricted to long-chain PUFAs, as linoleic and linolenic acids had similar actions in the goldfish. The inhibitory action of EPA on testosterone production was reversible upon removal of the PUFA from medium. Testosterone production stimulated by the addition of the cAMP analogues, dibutyryl cAMP, and 8-bromo cAMP, was attenuated by PUFAs, suggesting that they act at a site distal to cAMP formation. A post-cAMP site regulating cholesterol availability may be involved as testosterone production induced by addition of 25OH-cholesterol was not affected by the PUFAs in either fish species. Together, these findings underscore the importance of lipids in ovarian physiology and suggest that PUFAs may participate in the regulation of ovarian steroidogenesis in teleost fish.
研究了多不饱和脂肪酸（PUFA）——二十碳五烯酸（EPA）、二十二碳六烯酸（DHA）和花生四烯酸（AA）——对金鱼和虹鳟鱼完全成熟的早熟卵巢卵泡体外类固醇生成的影响。EPA和DHA以剂量相关的方式抑制促性腺激素刺激的睾酮生成，但AA仅在最高测试剂量（400微摩尔）时具有抑制作用。单独的AA通过增加cAMP生成来刺激睾酮生成，但其他PUFA单独作用的效果不明显。PUFA的抑制作用并不局限于长链PUFA，因为亚油酸和亚麻酸在金鱼中具有类似作用。从培养基中去除PUFA后，EPA对睾酮生成的抑制作用是可逆的。添加cAMP类似物二丁酰cAMP和8-溴cAMP刺激的睾酮生成会被PUFA减弱，这表明它们作用于cAMP形成的远端位点。由于添加25-羟基胆固醇诱导的睾酮生成在两种鱼类中均不受PUFA影响，因此可能涉及一个调节胆固醇可用性的cAMP后位点。总之，这些发现强调了脂质在卵巢生理学中的重要性，并表明PUFA可能参与硬骨鱼卵巢类固醇生成的调节。
