Prostaglandins in Swine Blastocysts

Abstract

The activity of phospholipase A2 (PLA2) and the content of prostaglandins (PGF and PGE-A) in swine blastocysts were determined on Days 7 through 14 of gestation by using radioenzymatic and radioimmunoassay techniques. Both PLA2 activity and PG content increased in the blastocyst with age. PLA2 activity on Day 14 and PG content on Day 12 were significantly higher than those on earlier stages of pregnancy. The content of PGE-A was always greater than that of PGF and the difference became significant on Days 11 and 12 of pregnancy. It is suggested that PGs of embryonic origin may be associated with blastocyts elongation and migration as well as early pregnancy recognition in the pig.

Cyclooxygenase-1-derived PGE2 promotes cell motility via the G-protein-coupled EP4 receptor during vertebrate gastrulation

“…Analogous to other systems, these findings suggested that the zebrafish Ptges functions downstream of COX-1 during gastrulation to generate PGE 2 . Accordingly measurements of prostaglandin levels using mass spectrometry revealed the production of PGE 2 during gastrulation, along with PGF 2␣ (prostaglandin F 2␣ ) and PGI 2 (Cha et al 2005a), which parallels studies demonstrating the presence of PGE 2 and PGF 2␣ in developing mammalian blastocysts (Davis et al 1983).…”

“…Given the vital role of prostaglandins in normal physiologic settings, it has been hypothesized that the maternal contribution of prostaglandins in the placenta allows the prostaglandindeficient embryos to develop normally (Reese et al 2000(Reese et al , 2001. Consistent with this notion, mammalian blastocysts produce high levels of PGE 2 and PGF 2␣ (Dey et al 1980;Davis et al 1983), and murine blastocysts cultured outside of the uterus do not survive in the presence of COX inhibitors (H. Wang and S.K. Dey, pers.…”

Implantation and Establishment of Pregnancy in the Pig

“…IL1B can also stimulate phospholipase A2 (PLA2) (Kol et al 2002 ) which increases membrane fl uidity through the release of arachidonic acid from the phospholipid bilayer of the cell membrane. The increase of plasminogen activator and PLA2 activity during elongation of the conceptus (Davis et al 1983 ) would be consistent with a role for IL1B2 in the induction of rapid cellular remodeling. The release of arachidonic acid from the conceptus trophoblast contributes to increases in secretion of PGs from the conceptus during and following elongation as conceptus expression of PTGS2 also increases (Wilson et al 2002 ).…”

Production of Steroids and Release of Prostaglandins by Spherical Pig Blastocysts in vitro

“…Changes in levels of certain hormones, proteins and minerals in histotroph before day 12 of pregnancy (Geisert et al 1982a;Zavy et al 1984; will, therefore, be independent of changes in maternal endocrine function, suggesting that preimplantation embryos have a capacity to modify their own microenvironment before the maternal recognition of pregnancy. In this respect, hormones secreted by blastocysts could induce local changes in endometrial activity which are consistent with changes in the composition of histotroph during the first 10 days of pregnancy (Knight et al 1973;Basha et al 1980;Adams et al 1981;Geisert et al 1982a) and several groups have now reported capacities for steroid Heap et al 1981) and PG (Watson and Patek 1979;Davis et al 1983) synthesis by dispersed tissues of pig blastocysts collected after day 10 of gestation. Specific inhibition of endocrine activities of blastocysts is associated with impaired implantation, degenerative changes and early intrauterine mortality EI-Banna et al 1970;Hoffman 1978;Hurst and MacFarlane 1981).…”