Retrograde and local destination transfer of uterine prostaglandin E2 in early pregnant sow and its physiological consequences

Stefańczyk-Krzymowska, Stanisława; Wąsowska, Barbara; Chłopek, J.; Gilun, Przemysław; Grzegorzewski, Waldemar; Radomski, Michal

doi:10.1016/j.prostaglandins.2006.07.004

Cited by 18 publications

(13 citation statements)

References 30 publications

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“…Whether or not FSH contributes to influence luteal function remains speculation. If we were to accept previous reports that steroid treatments in pigs [8,9] or GnRH in horses [30,31] benefit pregnancy outcome, other routes of GnRH mediation could also be evident, such as those influencing processes of uterine estrogen synthesis [32], endometrial angiogenesis, utero-ovarian counter-current transfer [33] and P4 dependent immunomodulation [34,35]. Furthermore, direct effects of GnRH on ovarian luteal cells [36] and on uterine tissues mediated by extrapituitary receptors should be recognized [37,38].…”

Section: Gnrh Agonist Effects In Pregnant Giltsmentioning

confidence: 96%

Endocrine Effects of GnRH Agonist Application to Early Pregnant Gilts

Brüssow

Schneider

Wollenhaupt

et al. 2011

Journal of Reproduction and Development

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Abstract. The hypothesis of the present study was that a GnRH agonist application at early pregnancy would alter the pattern of the key reproductive hormones LH and FSH, and subsequently that of estradiol (E2) and especially progesterone (P4), and improve the conditions for embryo survival in early pregnant gilts. Therefore, the endocrine effects of a GnRH agonist (GnRHa) application to gilts (n=11 GnRHa treated, n=9 saline Controls) were studied in blood samples from the Vena cava caudalis. GnRHa injected on Day 12 after insemination induced elevated (P<0.01) LH and FSH levels for at least 180 min. However, subsequent LH concentrations were not altered up to Day 21 of pregnancy. LH pulse number, estimated in 6-h period samples on Days 13, 15 and 17, was not influenced by treatment and pregnancy. LH pulse amplitude was decreased (P<0.05) on Days 13 to 17 in pregnant gilts of both groups, but not in nonpregnant animals. In pregnant GnRHa-treated gilts, the basal LH level was elevated compared with the Controls (P<0.01). Additionally, differences (P<0.05) in basal LH were present between the pregnant and nonpregnant animals. The P4 and E2 secretion pattern was not affected by GnRHa. P4 concentrations increased (P<0.01) from Day 10 to Day 14 regardless of the treatment. P4 revealed a pulse-like pattern, but without a definite relation to the LH pulse characteristics. Also, pregnancy rate (73 vs. 67%) and the number of fetuses (12.8 ± 2.3 vs. 11.6 ± 2.3) were unaffected in the treated and Control gilts, respectively. The present study did not confirm the initial hypothesis that a GnRHamediated LH effect could alter ovarian steroid secretion and favorably support early embryo development and pregnancy outcome. Key words: GnRH-agonist, LH, Pig, Pregnancy, Progesterone (J. Reprod. Dev. 57: [242][243][244][245][246][247][248] 2011) rogesterone from the developing corpus luteum (CL) is the most important driver of endometrial secretion and receptivity for early conceptus development and implantation in pigs [1,2]. About 30% of porcine conceptuses are lost during the peri-implantation period [3], and this period is susceptible to a lack of P4. It has been shown that a concentration of 4 ng/ml P4 in peripheral blood appears to be minimum required for maintenance of pregnancy [4]. Attempts have been undertaken to improve pregnancy rate or reduce pregnancy losses in pigs by steroid or gonadotropin application [5][6][7]. Since steroid treatment may improve litter size [8,9], the question is whether luteal P4 secretion can be enhanced by GnRH-induced LH stimulation. This is because LH is considered to be essential in pigs for support of luteal P4 production and pregnancy outcome as demonstrated by passive immunization with anti-LH serum or blockage of LH secretion and regulation of ovarian function by a GnRH antagonist [10,11].The hypothesis of the present study was that a single GnRH agonist application, given on Day 12 after insemination, would alter the pattern of the key reproductive hormones LH and FSH, and subsequentl...

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Section: Gnrh Agonist Effects In Pregnant Giltsmentioning

confidence: 96%

Endocrine Effects of GnRH Agonist Application to Early Pregnant Gilts

Brüssow

Schneider

Wollenhaupt

et al. 2011

Journal of Reproduction and Development

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“…Greater PGE 2 secretion in the gravid uterine horn of unilaterally pregnant pigs is associated with increased luteal weights and progesterone concentrations of ipsilateral CLs (Christenson et al 1994). The infusion of PGE 2 into the ovarian artery elevates the concentration of progesterone in the ovarian venous blood on days 13 and 14 of pregnancy (Stefanczyk-Krzymowska et al 2006).…”

Section: Role Of Pgs During Pregnancy Establishmentmentioning

confidence: 98%

Novel insights into the mechanisms of pregnancy establishment: regulation of prostaglandin synthesis and signaling in the pig

Wacławik

2011

Reproduction

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Ovarian progesterone induces essential changes leading to a temporary state of uterine receptivity for conceptus implantation. Estrogens secreted by the porcine conceptus on days 11 and 12 of pregnancy provide the initial signal for maternal recognition of pregnancy and maintenance of a functional corpus luteum (CL) for continued production of progesterone. As prostaglandins F 2a (PGF 2a ) and E 2 (PGE 2 ) exert opposing actions on the CL, a tight control over their synthesis and secretion is critical either for the initiation of luteolysis or maintenance of pregnancy. One of the supportive mechanisms by which conceptus inhibits luteolysis is changing PG synthesis in favor of luteoprotective PGE 2 . Conceptus PGE 2 could be amplified by PGE 2 feedback loop in the endometrium. In pigs, as in other species, implantation and establishment of pregnancy is associated with upregulation of expression of proinflammatory factors, which include cytokines, growth factors, and lipid mediators. The conceptus produces inflammatory mediators: interferon g and interferon d, interleukins IL1B and IL6, and PGs, which probably activate inflammatory pathways in the endometrium. The endometrium responds to these embryonic signals by enhancing further progesterone-induced uterine receptivity. Understanding the mechanisms of pregnancy establishment is required for translational research to increase reproductive efficiencies and fertility in humans and animals.

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“…Currently, intravaginal sponges are routinely applied to synchronize estrus and improve pregnancy rates in sheep. Increasing knowledge about the local transfer of steroids and prostaglandins (PGs) in the porcine reproductive system (Stefanczyk- Krzymowska et al 2006), as well as the paramount role of prostaglandin E 2 (PGE 2 ) and 17β-estradiol (E 2 ) during early pregnancy in the pig, led us to design the present study. The potential value of the intravaginal hormone delivery route is enhanced by the observation that prolongation of CL function after multiple injections of milligram amounts of estrogen could not mimic the hormonal status of natural pregnancy in the pig (Ziecik et al 1986).…”

Section: Discussionmentioning

confidence: 99%

“…It resulted in 2-to 4-fold higher P 4 levels in the uterine artery than in systemic blood. Further studies revealed the local transfer of steroids and prostaglandins (PGs) in the porcine reproductive tract (Stefanczyk-Krzymowska et al 2006). Interestingly, vaginal administration of suppositories containing E 2 and P 4 had beneficial effects on the embryo development and survival in pigs (Chłopek et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Effect of vaginal administration of prostaglandin E2 and/or 17β-estradiol on luteal function and histological characteristics of the cervix in cyclic pigs

Przygrodzka¹,

Andronowska²,

Janowski³

et al. 2014

Polish Journal of Veterinary Sciences

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The overall objective of this study was to examine the effect of vaginal administration of prostaglandin E 2 (PGE 2 ) and/or17β-estradiol (E 2 ) on luteal function maintenance and histological properties of the porcine cervix. For this purpose, crossbred gilts were divided into three groups (n=5 per group) supplied on days 11-16 of the estrous cycle with suppositories containing: (1) placebo (Group I, Control); (2) 0.4 mg of E 2 (Group II); (3) 0.4 mg of E 2 and 2 mg of PGE 2 (Group III). Blood samples were collected on days 11-19 of the estrous cycle to determine the concentration of progesterone (P 4 ). Additionally, to examine local effects of the hormones applied, segments from the uterine and vaginal parts of the cervix and from the ovaries were collected post-mortem. Prolonged luteal function and extended synthesis of P 4 were observed in 2 of 5 gilts receiving PGE 2 and E 2 simultaneously (Group III). Then, these gilts were subdivided into Group IIIA (n=2; presence of corpora lutea on the ovaries) and Group IIIB (n=3; lack of corpora lutea). Increased levels of plasma P 4 were observed in Group IIIA on days 15-19 compared to Group IIIB and on days 16-19 compared to Group I and Group II (P<0.05; P<0.01; P<0.001, respectively). In the cervix of gilts in Groups II and III, enlarged blood vessels in the lamina propria of both parts of the cervix were observed. Furthermore, in Group II the epithelium of the uterine part of the cervix was thicker (P<0.001). Our study confirmed the proposed luteotrophic/antiluteolytic actions of E 2 and PGE 2 applied intravaginally. These results are significant considering that very low doses of E 2 were used when compared to previous attempts. Despite the inadequate response to treatments in some of the gilts, the local effects of these hormones on the histological properties of the porcine cervix suggest that further improvements in the vaginal administration route might help to elaborate new methods for enhancing the luteal function in the pig.

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Retrograde and local destination transfer of uterine prostaglandin E2 in early pregnant sow and its physiological consequences

Cited by 18 publications

References 30 publications

Endocrine Effects of GnRH Agonist Application to Early Pregnant Gilts

Endocrine Effects of GnRH Agonist Application to Early Pregnant Gilts

Novel insights into the mechanisms of pregnancy establishment: regulation of prostaglandin synthesis and signaling in the pig

Effect of vaginal administration of prostaglandin E2 and/or 17β-estradiol on luteal function and histological characteristics of the cervix in cyclic pigs

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