Niesert S, Christopherson W, Korte K, Mitchell M D, MacDonald P C, Casey M L
Am J Obstet Gynecol. 1986 Dec;155(6):1348-52. doi: 10.1016/0002-9378(86)90172-9.
Amnion is believed to be a tissue of central importance in the biochemical processes of parturition. In this tissue, prostaglandin E2 is the near exclusive prostaglandin produced. And although the production of prostaglandin E2 is increased during labor in women, the levels of the major metabolite of prostaglandin E2 in maternal plasma are not elevated; rather, the levels of 13,14-dihydro-15-ketoprostaglandin F2 alpha, the major circulating metabolite of prostaglandin F2 alpha, are increased strikingly. Because of this apparent paradox, we considered the possibility that prostaglandin E2, originating in amnion, chorion laeve, or decidua vera, is converted to prostaglandin F2 alpha in decidua vera by the action of prostaglandin E2-9-ketoreductase. We found that prostaglandin E2 9-ketoreductase, the enzyme that catalyzes the conversion of prostaglandin E2 to F2 alpha, is present in cytosolic fractions prepared from homogenates of uterine decidua vera tissue. The specific activity of 9-ketoreductase in cytosolic fractions of decidua of six women varied from 3.2 to 155 pmol X min-1 X mg-1 protein. We also evaluated the conversion of exogenous prostaglandin E2 to F2 alpha in intact human endometrial stromal cells in monolayer culture. We found that prostaglandin E2, added to the culture medium, was converted to prostaglandin F2 alpha by endometrial stromal cells that were maintained in the presence of inhibitors of prostaglandin synthase. The extent of conversion of exogenous prostaglandin E2 to F2 alpha, however, was low relative to the specific activity of prostaglandin E2 9-ketoreductase found in decidual cytosol. These findings are consistent with the possibility that prostaglandin E2 formed in decidua vera tissue may be converted in that tissue to prostaglandin F2 alpha by 9-ketoreductase; on the other hand, prostaglandin E2 formed in contiguous tissues probably is not converted significantly to prostaglandin F2 alpha by decidual 9-ketoreductase.
羊膜被认为是分娩生化过程中至关重要的组织。在该组织中，前列腺素E2几乎是唯一产生的前列腺素。尽管女性分娩期间前列腺素E2的产量会增加，但母体血浆中前列腺素E2主要代谢物的水平并未升高；相反，前列腺素F2α的主要循环代谢物13,14-二氢-15-酮前列腺素F2α的水平却显著增加。由于存在这种明显的矛盾现象，我们考虑了这样一种可能性，即源自羊膜、平滑绒毛膜或真蜕膜的前列腺素E2，在真蜕膜中通过前列腺素E2-9-酮还原酶的作用转化为前列腺素F2α。我们发现，催化前列腺素E2转化为F2α的酶——前列腺素E2 9-酮还原酶，存在于从子宫真蜕膜组织匀浆制备的胞质组分中。六名女性蜕膜胞质组分中9-酮还原酶的比活性在3.2至155 pmol·min⁻¹·mg⁻¹蛋白质之间变化。我们还评估了单层培养的完整人子宫内膜基质细胞中外源性前列腺素E2向F2α的转化。我们发现，添加到培养基中的前列腺素E2，在存在前列腺素合酶抑制剂的情况下，被子宫内膜基质细胞转化为前列腺素F2α。然而，相对于在蜕膜胞质溶胶中发现的前列腺素E2 9-酮还原酶的比活性，外源性前列腺素E2向F2α的转化程度较低。这些发现与以下可能性一致，即真蜕膜组织中形成的前列腺素E2可能在该组织中通过9-酮还原酶转化为前列腺素F2α；另一方面，相邻组织中形成的前列腺素E2可能不会被蜕膜9-酮还原酶显著转化为前列腺素F2α。
