Costine Beth A, Inskeep E Keith, Blemings Kenneth P, Flores Jorge A, Wilson Matthew E
Division of Animal and Veterinary Sciences, West Virginia University, Morgantown, WV, USA.
Domest Anim Endocrinol. 2007 Feb;32(2):106-21. doi: 10.1016/j.domaniend.2006.01.003. Epub 2006 Feb 20.
During maternal recognition of pregnancy, the conceptus stimulates endometrial secretion of PGF2alpha and PGE2. However, PGF2alpha is less effective in causing luteal regression in pregnant than in non-pregnant ewes. Experiments were conducted to elucidate mechanisms for reduced luteal sensitivity to PGF2alpha during maternal recognition of pregnancy. Corpora lutea (CL) were collected from pregnant and non-pregnant ewes 0, 4, or 12h following treatment with PGF2alpha on day 12 after estrus. Luteal PTGHS2 mRNA did not differ due to PGF2alpha or pregnancy status. Luteal PTGES mRNA was reduced in both pregnant and non-pregnant ewes after PGF2alpha treatment; while, luteal PTGFS mRNA was reduced 4h after PGF2alpha in pregnant, but not non-pregnant ewes. The result was a greater ratio of PTGES to PTGFS mRNA in pregnant ewes. Luteal mRNA for HPGD did not differ between pregnant and non-pregnant ewes on day 12. Luteal END1 mRNA was reduced in pregnant as compared to non-pregnant ewes prior to PGF2alpha challenge. Luteal END1 mRNA was increased after PGF2alpha in pregnant and non-pregnant ewes; however, ECE1 mRNA was reduced 4h after PGF2alpha in pregnant, but not non-pregnant ewes. The in vitro conversion of PGF2alpha to PGFM was greater in CL of pregnant than non-pregnant ewes at day 14. Luteal conversion of PGF2alpha to PGFM appears to be regulated post-transcriptionally. During maternal recognition of pregnancy, mechanisms of reduced luteal sensitivity to PGF2alpha may include a shift in prostaglandin production to the luteotropin PGE2, a reduction of ECE1 mRNA, and increased catabolism of PGF2alpha.
在母体识别妊娠期间，孕体刺激子宫内膜分泌前列腺素F2α（PGF2α）和前列腺素E2（PGE2）。然而，与未怀孕的母羊相比，PGF2α在引起怀孕母羊黄体退化方面效果较差。进行了实验以阐明在母体识别妊娠期间黄体对PGF2α敏感性降低的机制。在发情后第12天用PGF2α处理0、4或12小时后，从怀孕和未怀孕的母羊收集黄体。黄体前列腺素内过氧化物合酶2（PTGHS2）mRNA不因PGF2α或妊娠状态而有所不同。PGF2α处理后，怀孕和未怀孕母羊的黄体前列腺素E合成酶（PTGES）mRNA均降低；而PGF2α处理4小时后，怀孕母羊的黄体前列腺素F合成酶（PTGFS）mRNA降低，未怀孕母羊则未降低。结果是怀孕母羊中PTGES与PTGFS mRNA的比例更高。在第12天，怀孕和未怀孕母羊的黄体15-羟基前列腺素脱氢酶（HPGD）mRNA没有差异。在PGF2α刺激之前，与未怀孕母羊相比，怀孕母羊的黄体内皮素1（END1）mRNA降低。PGF2α处理后，怀孕和未怀孕母羊的黄体END1 mRNA均增加；然而，PGF2α处理4小时后，怀孕母羊的黄体内皮素转换酶1（ECE1）mRNA降低，未怀孕母羊则未降低。在第14天，怀孕母羊黄体中PGF2α向13,14-二氢-15-酮-PGF2α（PGFM）的体外转化比未怀孕母羊的更大。PGF2α向PGFM的黄体转化似乎在转录后受到调节。在母体识别妊娠期间，黄体对PGF2α敏感性降低的机制可能包括前列腺素生成向促黄体生成素PGE2的转变、ECE1 mRNA的减少以及PGF2α分解代谢的增加。
