Studies on ovarian prostaglandin production in relation to ovulation in the rat

Brown, C.G.; Poyser, N.L.

doi:10.1530/jrf.0.0720407

Cited by 38 publications

(13 citation statements)

References 14 publications

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“…In the present study, there was also an increase in the follicular fluid concentration of 6-oxo-PGF ia , although the increase was not as great as those for PGE 2 and PGF 2 ,-Nevertheless, the highest concentration (54.4 ng/ml) of 6-oxo-PGF 'a found is the largest value yet recorded for any tissue in any species. An increase in the concentration of 6-oxo-PGF 'a at the time of ovulation in the rat ovary has been reported previously (Brown and Poyser, 1984). Overall, the present findings are consistent with ovarian prostaglandins having an essential rôle in ovulation in the pig.…”

Section: Introductionsupporting

confidence: 92%

“…There are changes in the concentration in the follicular fluid of steroid hormones (e.g. Short, 1961 ;Younglai, 1972 ;Moor et al, 1973 ;Baird and Fraser, 1975 ;McNatty et al, 1975 ;Channing and Coudert, 1976), gonadotrophic hormones (McNatty et al, 1975 ;Henderson, McNeilly and Swanston, 1982), prolactin (McNatty, Sawers and McNeilly, 1974) and prostaglandins (Tsafriri et al, 1972 ;LeMaire et al, 1973LeMaire et al, , 1975Brown and Poyser, 1984), in addition to enzymatic and structural modifications to the follicle wall (reviewed by Lipner, 1973 ;Espey, 1974Espey, , 1980Weir and Rowlands, 1977 ;Thibault and Levasseur, 1979) in diverse mammalian species. There are several reports of steroid hormone and of gonadotrophin concentrations in the Graafian follicles of pigs (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Ovarian follicular fluid concentrations of prostaglandins E₂, F_2α and I₂ during the pre-ovulatory period in pigs

Hunter¹,

Poyser²

1985

Reprod. Nutr. Dévelop.

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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.

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Section: Introductionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Ovarian follicular fluid concentrations of prostaglandins E₂, F_2α and I₂ during the pre-ovulatory period in pigs

Hunter¹,

Poyser²

1985

Reprod. Nutr. Dévelop.

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“…These results suggest that some of the steps of ovulation are mediated by this prostanoid (5). Indeed, luteinizing hormone surge leads to high expression of COX-2 in granulosa cells (6,7), and a large amount of PGE 2 is produced and released into the antral fluid (8). Recently, the importance of prostanoids in early pregnancy has been definitely shown in mice deficient in COX-2.…”

mentioning

confidence: 91%

Abortive expansion of the cumulus and impaired fertility in mice lacking the prostaglandin E receptor subtype EP ₂

Hizaki

Segi

Sugimoto

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

443

278

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Female mice lacking the gene encoding the prostaglandin (PG) E 2 receptor subtype EP 2 (EP 2 ؊͞؊ ) become pregnant and deliver their pups at term, but with a much reduced litter size. A decrease in ovulation number and a much reduced fertilization rate were observed in EP 2 ؊͞؊ females without difference of the uterus to support implantation of wild-type embryos. Treatment with gonadotropins induced EP 2 mRNA expression in the cumulus cells of ovarian follicles of wild-type mice. The immature cumuli oophori from wildtype mice expanded in vitro in response to both folliclestimulating hormone and PGE 2 , but the response to PGE 2 was absent in those from EP 2 ؊͞؊ mice. Cumulus expansion proceeded normally in preovulatory follicles but became abortive in a number of ovulated complexes in EP 2 ؊͞؊ mice, indicating that EP 2 is involved in cumulus expansion in the oviduct in vivo. No difference in the fertilization rate between wild-type and EP 2 ؊͞؊ mice was found in in vitro studies using cumulusfree oocytes. These results indicate that PGE 2 cooperates with gonadotropin to complete cumulus expansion for successful fertilization.Ovulation and fertilization are key processes in mammalian female reproduction, which is highly regulated by pituitary gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone. These hormones induce a number of preovulatory processes, including follicular development, oocyte maturation, cumulus expansion, and rupture of antral follicles (1). The ovulated eggs move to the oviducts, and timely interaction between an egg and a sperm then leads to successful fertilization (2). Undoubtedly, these processes are initiated by the gonadotropins, but how gonadotropins regulate these processes remains unclear. It is known that some gonadotropin actions are mediated by other mediators. Prostanoids, the cyclooxygenase (COX)-metabolites of arachidonate, likely mediate the ovulatory actions of gonadotropins (3) because aspirin-like drugs that inhibit COX have been reported to inhibit spontaneous and gonadotropin-primed ovulation in many species (4). Prostaglandin E 2 (PGE 2 ), a dominant prostanoid in the ovary, can reverse the inhibitory effect of aspirin-like drugs, when administered simultaneously. These results suggest that some of the steps of ovulation are mediated by this prostanoid (5). Indeed, luteinizing hormone surge leads to high expression of COX-2 in granulosa cells (6, 7), and a large amount of PGE 2 is produced and released into the antral fluid (8). Recently, the importance of prostanoids in early pregnancy has been definitely shown in mice deficient in COX-2. The COX-2 Ϫ͞Ϫ animals showed a reduction in ovulation number and severe failure in fertilization as well as defects in the ability of the uterus to receive implants and to undergo decidualization (9). The result that not only ovulation but fertilization was also severely affected indicates that prostanoids play a role in one of a series of preovulatory processes that are required for both ovulation and fert...

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“…We have therefore hypothesized that suppression of luteal angiogenesis in COX-2 inhibitor-treated rats may be due to a decrease in the stimulatory effect of PGE 2 on angiogenesis (Sakurai et al 2003), which is probably caused by the reduction in PGE 2 secretion in the CL. In the ovary, follicular PGE 2 concentrations gradually increase during the follicular phase, and PGE 2 levels are markedly elevated in mature granulosa cells after the LH surge and remain high during the development of the newly formed CL (Brown & Poyser 1984). Considering that luteinized granulosa cell is a major component in early CL and secretes PGE 2 , we can suppose that SLC-derived secreted PGE 2 might contribute to luteal angiogenesis during the early stage of CL formation in a paracrine fashion in vivo, because the examination of the impact of co-culture with SLCs revealed that the factor(s) that was secreted from SLCs and was inhibited by the COX-2 inhibitor promoted angiogenesis (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Our previous study showed that the activity of cyclooxygenase 2 (COX-2) is associated with the formation of a functional CL via the stimulation of angiogenesis in vivo (Sakurai et al 2003), and that VEGF stimulates prostaglandin E 2 (PGE 2 ) production by stimulating COX-2 expression in cultured rat luteal cells (Sakurai et al 2004). In the ovary, the concentration of PGE 2 is increased in the follicular fluid immediately before and after ovulation in Graafian follicles (Brown & Poyser 1984, Arosh et al 2004. PGE 2 can modulate vascular permeability and angiogenesis (Nie & Honn 2004).…”

Section: Introductionmentioning

confidence: 99%

Stimulation of tube formation mediated through the prostaglandin EP2 receptor in rat luteal endothelial cells

Sakurai¹,

Suzuki²,

Yoshie³

et al. 2011

Journal of Endocrinology

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To explore the role of prostaglandin E 2 (PGE 2 ) in angiogenesis in the developing corpus luteum, luteal microvascular endothelial-like cells (luteal ECs) were prepared from highly luteinizing ovaries of rats using the percoll density gradient method. The cells abundantly expressed the mRNAs of the endothelial markers CD31 (PECAM-1) and responded to the vascular endothelial growth factor (VEGF) to form in vitro tube structures on Matrigel. Cyclooxygenase (COX) inhibitors significantly suppressed tube formation in luteal ECs, whereas PGE 2 counteracted the COX inhibitorinduced blockage. PGE 2 -induced tube formation was blocked by a cyclic AMP-dependent protein kinase A (PKA) inhibitor, H89. The antagonist against the PGE receptor type 2 (EP2 receptor), AH6809, completely inhibited PGE 2 -induced tube formation and partly suppressed the VEGF-induced tube formation but did not attenuate PGE 2 -induced phosphorylation of both AKT kinase and extracellular signal-regulated kinase 1/2. VEGF significantly enhanced the expression of COX-2 mRNAs detected by realtime RT-PCR and PGE 2 secretion into the media measured by ELISA in luteal ECs. In turn, PGE 2 stimulated VEGF expression. In vitro co-culture of luteal ECs with steroidogenic luteal cells (SLCs) promoted tube formation. Pre-treatment of SLCs with VEGF further enhanced tube formation of ECs, and this effect was blocked by the COX-2 inhibitor. This stimulatory effect was inhibited by treatment with AH6809. These data indicate that PGE 2 exerts a direct stimulatory effect on tube formation mainly via the EP2 receptor/PKA signaling in luteal ECs. Our results suggest the possibility that the endogenous PGE 2 that is produced from luteinizing follicular cells as well as ECs may stimulate luteal angiogenesis.

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Studies on ovarian prostaglandin production in relation to ovulation in the rat

Cited by 38 publications

References 14 publications

Ovarian follicular fluid concentrations of prostaglandins E₂, F_2α and I₂ during the pre-ovulatory period in pigs

Ovarian follicular fluid concentrations of prostaglandins E₂, F_2α and I₂ during the pre-ovulatory period in pigs

Abortive expansion of the cumulus and impaired fertility in mice lacking the prostaglandin E receptor subtype EP ₂

Stimulation of tube formation mediated through the prostaglandin EP2 receptor in rat luteal endothelial cells

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Studies on ovarian prostaglandin production in relation to ovulation in the rat

Cited by 38 publications

References 14 publications

Ovarian follicular fluid concentrations of prostaglandins E 2, F2α and I2 during the pre-ovulatory period in pigs

Ovarian follicular fluid concentrations of prostaglandins E 2, F2α and I2 during the pre-ovulatory period in pigs

Abortive expansion of the cumulus and impaired fertility in mice lacking the prostaglandin E receptor subtype EP 2

Stimulation of tube formation mediated through the prostaglandin EP2 receptor in rat luteal endothelial cells

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Ovarian follicular fluid concentrations of prostaglandins E₂, F_2α and I₂ during the pre-ovulatory period in pigs

Ovarian follicular fluid concentrations of prostaglandins E₂, F_2α and I₂ during the pre-ovulatory period in pigs

Abortive expansion of the cumulus and impaired fertility in mice lacking the prostaglandin E receptor subtype EP ₂