Gonadotropin releasing hormone receptor gene and protein expression and immunohistochemical localization in bovine uterus and oviducts

Singh, Rajinder; Graves, Marcia L.; Roskelley, Calvin D.; Giritharan, G.; Rajamahendran, R.

doi:10.1016/j.domaniend.2007.09.004

Cited by 18 publications

(13 citation statements)

References 32 publications

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“…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]. Likewise, the induced LH secretion might affect the production of prostaglandins and steroids after binding to specific uterine receptors [39][40][41].…”

Section: Gnrh Agonist Effects In Pregnant Giltsmentioning

confidence: 99%

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: 99%

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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“…Recent research has demonstrated the ligand independent activation of steroid hormone receptors by some growth factors, neurotransmitters and cytokines (Blaustein 2004). Most recently, we demonstrated the presence of GnRH-R in both the follicular and luteal phase bovine endometrium (Singh et al 2008). Some of the factors involved in the ligand independent activation of steroid hormone receptors share common cell signaling pathways with GnRH.…”

Section: Discussionmentioning

confidence: 85%

“…The recent research in mammalian reproductive biology has demonstrated that GnRH modulates gonadal steroidogenesis, cellular proliferation, apoptosis and implantation (Ramakrishnappa et al 2005). Most recently, we demonstrated GnRH-R in follicular and luteal phase bovine endometrium and oviducts (Singh et al 2008). Endometrium is a dynamic structure and is always under the influence of estrogen and progesterone (Moutsatsou and Sekeris 1997), exerting their actions through estrogen (ERa and ERb) and progesterone receptors (PR), respectively.…”

mentioning

confidence: 99%

GnRH agonist (buserelin) up regulates estrogen receptor α mRNA but not estrogen receptor β and progesterone receptor mRNA in bovine endometrium in vitro

Singh¹,

Pretheeban²,

Rajamahendran³

2009

Can. J. Anim. Sci.

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Singh, R., Pretheeban, T. and Rajamahendran, R. 2009. GnRH agonist (buserelin) up regulates estrogen receptor a mRNA but not estrogen receptor b and progesterone receptor mRNA in bovine endometrium in vitro. Can. J. Anim. Sci. 89: 467Á473. The local modulatory role of gonadotropin releasing hormone (GnRH), gonadotropin releasing hormone receptor (GnRH-R) system in regulating steroid hormone receptors at the endometrial level is still not known. Estrogen and progesterone maintain uterine functions by acting through their corresponding receptors; estrogen receptors (ERa and ERb) and progesterone receptors (PR). We recently demonstrated GnRH-R in bovine endometrium and find the coexistence of GnRH and steroid hormone receptors in endometrium as interesting. Our objective was to determine the effect of a GnRH agonist (buserelin), on the expression of ERa, ERb, and PR messenger RNA (mRNA) in bovine endometrium. Reproductive tracts were collected from slaughtered cows at a local abattoir, and endometrial explants were treated with buserelin (0, 200, 500, 1000 ng mL(1 respectively), GnRH antagonist-antide (500 ng mL (1 ) and antide'buserelin (500' 200 ng mL(1 ) for 6 h and stored at (808C for RNA extraction. Two micrograms of total RNA was subjected to reverse transcription polymerase chain reaction, PCR products electrophoresed (2% agrose gel); visualized and statistically analyzed. The results showed that buserelin (200 ng mL(1 ) increased the expression of ERa in the luteal phase endometrium. In addition, the expression of endometrial ERa was greater during the follicular than luteal phase. This up regulation of ERa mRNA in luteal phase endometrium suggests that GnRH administration may influence pregnancy in bovines.

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“…In fact, ligandspecific binding sites were demonstrated to be present in many reproductive tissues, including the ovary [11,[127][128][129][130], oviduct [131], uterus [12,131,132], placenta [133], breast [14], testis [134][135][136], prostate [9], sperm and embryos [131], in a wide range of mammals. Even if it has been reported that extrapituitary GnRH-R is identical to the pituitary version, its expression on cell surfaces in extrapituitary sites is low as compared to that of the pituitary version [137,138].…”

Section: Gnrh/gnrh Receptor System In Neoplasia and Its Effect On Nementioning

confidence: 99%

The Pharmacological Pathways of GnRH Mediating the Inhibition of Mammary Tumours: Implications in Humans and Domestic Animals

Rizzo¹,

Spedicato²,

Mutinati³

et al. 2012

CMC

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The Gonadotropin-Releasing Hormone (GnRH) exists in two isoforms, GnRH-I and GnRH-II, in most vertebrates, including humans. Both of these isoforms and their respective receptors have been found in many healthy and pathologic extra nervous system tissues, such as cells found in cancers of the reproductive systems and, in particular, in breast cancer. GnRH analogues are used as therapeutic agents in the case of sex-hormone-dependent tumours. Besides acting as suppressors of steroidogenesis, GnRH analogues seem to interfere with mitogenic signal transduction pathways, thus behaving as negative regulators of tumour growth and progression. GnRH analogues counteract the proliferating effects of both epidermal growth factor (EGF) and insulin like growth factor (IGF-I); additionally, it affects the mitogen-activated protein kinase (MAPK) cascade and modulates the activity of the urokinase-type plasminogen activator (uPA)/plasminogen activator inhibitory (PAI) system, which is involved in the process of metastasis. In addition, GnRH analogues decrease the expression of many growth factors involved in the development of human uterine myomas (as well as endometriotic tissue), such as the vascular endothelial growth factor (VEGF), which is deeply implied in the angiogenesis of many benign and malignant tumours, including breast cancer. Angiogenesis is one of the primary processes leading to the progression and metastasis of breast cancer cells, and a key therapeutic goal in the fight against tumours is the blocking of new vessel sprouts. Given these premises, this review provides an update on the background of anti-neoplastic properties of GnRH analogues..

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Gonadotropin releasing hormone receptor gene and protein expression and immunohistochemical localization in bovine uterus and oviducts

Cited by 18 publications

References 32 publications

Endocrine Effects of GnRH Agonist Application to Early Pregnant Gilts

Endocrine Effects of GnRH Agonist Application to Early Pregnant Gilts

GnRH agonist (buserelin) up regulates estrogen receptor α mRNA but not estrogen receptor β and progesterone receptor mRNA in bovine endometrium in vitro

The Pharmacological Pathways of GnRH Mediating the Inhibition of Mammary Tumours: Implications in Humans and Domestic Animals

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