Ovarian follicular fluid concentrations of prostaglandins E ₂, F_2α and I₂ during the pre-ovulatory period in pigs

Abstract

Summary. The concentrations of prostaglandin (PG) E 2 , PGF 2a and PG1 2 (measured as 6-oxo-PGF I ) in follicular fluid collected from the ovaries of mature, cycling pigs during the immediate pre-ovulatory period have been estimated by radioimmunoassay. The concentrations of all three prostaglandins were low 24-32 hrs before the expected time of ovulation, with the ratio of the mean concentrations of PGE 2 , PGF 2. and 6-oxo-PGF 1a being 0.7:1.1:1.0. The concentration of PGE 2 showed a small increase during the next 22 hrs but, in the 2 hr period before the expected time of ovulation, the mean concentrations of PGE 2 , PGF 2a and 6-oxo-PGF la increased 119-, 11-and 5-fold, respectively, which produced a ratio of these mean concentrations of 14.8:2.2:1.0. One sample of follicular fluid contained the highest concentration of 6-oxo-PGF ia (54.4 ng/ml) yet reported for any tissue from any species, but this concentration was still lower than those of PGE 2 (529 ng/ml) and PGF 2 , (94.6 ng/ml). These results show that prostaglandin concentrations increase in the follicular fluid of mature, cycling pigs in the immediate preovulatory period, with PGE 2 being the predominant prostaglandin produced. In « preovulatory » follicles which failed to ovulate, prostaglandin concentrations were at baseline values. The findings in this study are consistent with follicular prostaglandins being essential for ovulation in the pig.Introduction.

Expression and possible role of fibroblast growth factor family members in porcine antral follicles during final maturation

“…The periovulatory group is defined and selected by the very high ascent of PGF2a level in FF. The level increases in such a way a few hours before ovulation, as shown for the pig (Hunter & Poyser 1985) and cow (Berisha et al 2006a). The typical descent of CYP19A1 and LHR mRNA expression confirms further our classification.…”

A preovulatory temperature gradient between the isthmus and ampulla of pig oviducts during the phase of sperm storage

“…More specifically, oviduct tissues are known to have receptors for steroid hormones, prostaglandins and relaxin, and an involvement of these follicular hormones in triggering the phase of sperm activation and release is probable (Hunter, 1984). Prostaglandins, in particular, may act directly or via Ca2 + fluxes to promote enhanced motility (Kelly, 1981;Aitken & Kelly, 1985), and ovarian follicular prostaglandins of the E, F and I series increase more than 100-, 10-and 5-fold, respectively, in pigs just before ovulation (Hunter & Poyser, 1985). Hence, a local transfer of high concentrations of prostaglandins from preovulatory follicles to the oviducts might stimulate spermatozoa as well as contractile changes in the oviduct tissues, together ensuring that meeting of male and female gametes at the site of fertilization is closely co-ordinated.…”

Advancement of Ovulation in the Sow Related to Seminal Plasma Application before Insemination

“…Measurements of oestrogens and PGF2a in the uterine vein before and after intrauterine infusion of oestrogen solutions reveal a parallel rise of PGFza within a few minutes, so that the PG rise seems to be due to a specific oestrogen effect (Claus et al 1987). I t seems likely that a rise of PGFza in follicular fluid is fundamental for ovulation in the pig and other species (Hunter & Poyser 1985), a follicle stimulation via PGFza in uterine vein and ovarian artery must be considered further. If the application of seminal plasma during insemination of sows in standing heat has an influcence on ovulation time, this should be measurable by calculating the time of ovum fertilization or determining the time of ovulation directly.…”