Shirasuna Koumei, Asaoka Hitomi, Acosta Tomas J, Wijayagunawardane Missaka P B, Ohtani Masayuki, Hayashi Ken-Go, Matsui Motozumi, Miyamoto Akio
Department of Agricultural and Life Science, Obihiro University of Agriculture and Veterinary Medicine, Japan.
Reproduction. 2004 Aug;128(2):189-95. doi: 10.1530/rep.1.00183.
Prostaglandin (PG) F2alpha released from the uterus in a pulsatile fashion is essential to induce regression of the corpus luteum (CL) in the cow. In addition to the uterus, the CL has also been recognized as a site of PGF(2alpha) production. Therefore, this study aimed to determine the detailed dynamics of the releasing profile of CL-derived PGF2alpha together with uterus-derived PGF2alpha during spontaneous luteolysis in the cow. Non-lactating Holstein cows (n = 6) were surgically implanted with a microdialysis system (MDS) on day 15 (oestrus = day 0) of the oestrous cycle. Simultaneously, catheters were implanted to collect ovarian venous plasma ipsilateral to the CL as well as jugular venous plasma. The concentrations of PGF2alpha, 13,14-dihydro-15-keto-PGF2alpha (PGFM) and progesterone in the MDS and plasma samples were determined by enzyme immunoassays. The intra-luteal PGF2alpha secretion slightly increased after the onset of luteolysis (0 h) and drastically increased from 24 h, and was maintained at high levels towards the following oestrus. Furthermore, PGF2alpha was released from the CL into the ovarian vein in a pulsatile manner during spontaneous luteolysis. Also, the fact that intra-luteal secretion of PGF2alpha and PGFM showed a positive correlation indicates the existence of a local metabolic pathway for PGF2alpha in the CL. In conclusion, the present study clarified the real-time dynamics of uterus-derived PGF2alpha and CL-derived PGF2alpha during spontaneous luteolysis in the cow, and gives the first in vivo evidence that the CL releases PGF2alpha during spontaneous luteolysis in the cow. Although the physiological relevance of CL-derived PGF2alpha appears to be restricted to a local role as an autocrine/paracrine factor in the CL, overall results support the concept that the local release of PGF2alpha within the regressing CL amplifies the luteolytic action of PGF2alpha from the uterus.
以脉冲方式从子宫释放的前列腺素（PG）F2α对于诱导母牛黄体（CL）退化至关重要。除子宫外，CL也被认为是PGF(2α)产生的部位。因此，本研究旨在确定母牛自发黄体溶解过程中CL来源的PGF2α与子宫来源的PGF2α释放曲线的详细动态。在发情周期的第15天（发情日=第0天），对6头非泌乳荷斯坦奶牛进行手术植入微透析系统（MDS）。同时，植入导管以收集与CL同侧的卵巢静脉血浆以及颈静脉血浆。通过酶免疫测定法测定MDS和血浆样本中PGF2α、13,14-二氢-15-酮-PGF2α（PGFM）和孕酮的浓度。黄体溶解开始（0小时）后，黄体内部的PGF2α分泌略有增加，从24小时起急剧增加，并在随后的发情期保持在高水平。此外，在自发黄体溶解过程中，PGF2α以脉冲方式从CL释放到卵巢静脉中。而且，PGF2α和PGFM的黄体内部分泌呈正相关这一事实表明CL中存在PGF2α的局部代谢途径。总之，本研究阐明了母牛自发黄体溶解过程中子宫来源的PGF2α和CL来源的PGF2α的实时动态，并首次提供了体内证据，证明母牛在自发黄体溶解过程中CL释放PGF2α。尽管CL来源的PGF2α的生理相关性似乎仅限于在CL中作为自分泌/旁分泌因子的局部作用，但总体结果支持这样的概念，即退化黄体中PGF2α的局部释放会放大子宫中PGF2α的溶黄体作用。
