Olofsson J, Norjavaara E, Selstam G
Department of Physiology, University of Umeå, Sweden.
Prostaglandins Leukot Essent Fatty Acids. 1992 Jun;46(2):151-61. doi: 10.1016/0952-3278(92)90222-5.
The ability of de novo biosynthesis of prostaglandins (PGs) in individual whole corpora lutea (CL) obtained from sterile-mated adult pseudopregnant rats on different days of the luteal phase and the post-luteolytic period was evaluated. Production of PGs, progesterone and 20 alpha-dihydroprogesterone were determined after in vitro incubation of CL extirpated from Day 2 to Day 19 after mating. A time-relationship with increased accumulation of PGs in the medium was demonstrated from 18 s to 5 h, with large increments during the first 30 min. Basal accumulation of PGs in the incubation medium was highest for 6-keto-PGF1 alpha (the stable metabolite of prostacyclin) greater than PGE2 greater than PGF2 alpha greater than thromboxane B2 (TXB2) and basal accumulation of PGF2 alpha and PGE2 measured in the medium was maximal on Day 10-11 of pseudopregnancy, concomitantly with a decline in secretion of progesterone. Addition of arachidonic acid (AA) dose-dependently increased synthesis of PGs, with absolute amounts of PGE2 greater than 6-keto-PGF1 alpha greater than PGF2 alpha greater than TXB2 and addition of 14 microM indomethacin markedly inhibited accumulation of all PGs measured. Luteinizing hormone (LH, 10 micrograms/ml) stimulated progesterone secretion on all days during pseudopregnancy, but not on the post-luteolytic Day 19. LH increased PGF2 alpha, PGE2 and 6-keto-PGF1 alpha secretion on Day 13 of pseudopregnancy by 76%, 91% and 28%, respectively, but not on the other days tested. Furthermore, stimulation of PG-synthesis by addition of AA abrogated the LH-induced progesterone accumulation markedly, but only on Day 13 of pseudopregnancy. Epinephrine (5 micrograms/ml) increased production of progesterone and also PGs, but only on Day 2 of pseudopregnancy, whereas oxytocin (100 mIU/ml) was found to be without effect on progesterone as well as PG secretion on all days tested. The results of the present study demonstrates the independent ability of the rat CL to synthesize PGG/PGH2-derived prostaglandins, including the putative luteolysin PGF2 alpha. Secondly, we demonstrate that LH and AA-induced increases in PGF2 alpha and PGE2 production during the luteolytic period, may be an autocrine or paracrine mechanism involved in luteolysis.
对从处于黄体期和黄体溶解后不同天数的无菌交配成年假孕大鼠获得的单个完整黄体（CL）中前列腺素（PGs）的从头生物合成能力进行了评估。在交配后第2天至第19天摘除CL进行体外孵育后，测定PGs、孕酮和20α-二氢孕酮的产生。结果表明，从18秒到5小时，培养基中PGs的积累与时间呈正相关，在前30分钟内有大幅增加。孵育培养基中PGs的基础积累量以6-酮-PGF1α（前列环素的稳定代谢产物）最高，其次是PGE2、PGF2α、血栓素B2（TXB2），培养基中PGF2α和PGE2的基础积累量在假孕第10-11天达到最大值，同时孕酮分泌下降。添加花生四烯酸（AA）可剂量依赖性地增加PGs的合成，合成量依次为PGE2＞6-酮-PGF1α＞PGF2α＞TXB2，添加14μM吲哚美辛可显著抑制所测所有PGs的积累。促黄体生成素（LH，10μg/ml）在假孕期间的所有天数均可刺激孕酮分泌，但在黄体溶解后的第19天则无此作用。LH在假孕第13天可使PGF2α、PGE2和6-酮-PGF1α的分泌分别增加76%、91%和28%，但在其他测试天数则无此作用。此外，添加AA刺激PGs合成可显著消除LH诱导的孕酮积累，但仅在假孕第13天出现这种情况。肾上腺素（5μg/ml）可增加孕酮和PGs的产生，但仅在假孕第2天出现这种情况，而催产素（100 mIU/ml）在所有测试天数对孕酮和PGs分泌均无影响。本研究结果表明，大鼠CL具有独立合成PGG/PGH2衍生前列腺素的能力，包括假定的黄体溶解素PGF2α。其次，我们证明，在黄体溶解期，LH和AA诱导的PGF2α和PGE2产生增加可能是参与黄体溶解的一种自分泌或旁分泌机制。
