Endocrine, morphological, and cytological effects of a depot GnRH agonist in bovine

Schneider, Falk; Heleil, B.; Alm, H.; Torner, H.; Becker, Frank; Viergutz, Torsten; Nürnberg, Gerd; Kanitz, W.

doi:10.1016/j.anireprosci.2005.05.012

Cited by 10 publications

(5 citation statements)

References 54 publications

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“…The presence of the ovary and its local supply of P4 can favor the environment of the appendant uterine horn for implantation of embryos and fetal development. As previously reported [20,21], the local counter current transfer of P4 from ovar-…”

Section: Translational Researchsupporting

confidence: 75%

Influence of unilateral ovariectomy performed before ovulation on ovarian function, steroid hormone levels and development of porcine fetuses

Brüssow

Rátky

Kempisty

et al. 2018

TRVS

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Corpus luteum (CL) activity is closely linked with initiation and maintenance of pregnancy and with fetal development. The present study was aimed to analyze the impact of unilateral ovarian removal on ovarian function, steroid hormone level and fetal distribution and development. Unilateral ovariectomy (uni-OVX) was performed in gilts one day before ovulation (group SHORT, n = 24), 20 days before subsequent ovulation (group LONG, n = 23) or ovaries remained intact (group INTACT, n = 22). Gilts were inseminated by single fixed-time laparoscopic intrauterine insemination (LIUI) after hormonal estrus synchronization. Two days before the end of a 15 day long altrenogest feeding, a part of gilts (n = 23) were surgically fitted with a jugular vein catheter and blood samples were collected to determine of estradiol (E2) and progesterone (P4) concentrations. All animals were slaughtered on day 30 of gestation and ovarian features as well as the number, weight and distribution of fetuses recorded. Altogether, 48 gilts (70%) were pregnant and pregnancy rates did not differ between groups. Short term uni-OVX affected CL number compared to intact and long term OVX gilts (9.9 ± 0.8 vs. 20.6 ± 1.9 and 17.5 ± 0.8; P < 0.05) and the number of fetuses (8.7 ± 0.5 vs. 15.0 ± 1.0 and 14.4 ± 1.1; P<0.05), respectively. Weights of individual CL were not influenced by treatment. Fetuses were differently distributed in the uterine horns after uni-OVX. A higher (P<0.05) proportion of fetuses was present always in the horn which bore the ovary. In all groups, weights of fetuses from uterine horns with an active ovary was similar; however, fetuses of the OVX horn of the SHORT group were lighter (P < 0.05). Steroid hormone profile was typical for pregnant gilts, but differences were observed between groups. Both, the preovulatory E2 concentrations and the early luteal phase P4 levels were higher (P < 0.05) in gilts of the INTACT and LONG groups. In summary, compared to intact gilts, only long term uni-OVX could compensate ovarian development. Short term uni-OVX affects (1) the total number of CL and fetuses, (2) the distribution and weight of fetuses in the uterine horns and (3) steroid hormone levels. Therefore, the time window, but not the uni-OXV per se, which alters the local supply of progesterone, has an impact on fetal development and survival.

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Section: Translational Researchsupporting

confidence: 75%

Influence of unilateral ovariectomy performed before ovulation on ovarian function, steroid hormone levels and development of porcine fetuses

Brüssow

Rátky

Kempisty

et al. 2018

TRVS

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“…; Schneider et al . ). Thus, it is not yet clear regarding the exact effects and mechanisms of GnRH analog on reproductive performance in animals (Bertschinger et al .…”

Section: Introductionmentioning

confidence: 97%

“…Furthermore, very little is known about the expression of hormone receptors in the pituitary of ewes immunized actively with GnRHa (Ramakrishnappa et al 2005;Schneider et al 2006). Furthermore, very little is known about the expression of hormone receptors in the pituitary of ewes immunized actively with GnRHa (Ramakrishnappa et al 2005;Schneider et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Such effects of GnRH agonists, especially alarelin acetate, on pituitary and ovaries in sheep are still unknown. Furthermore, very little is known about the expression of hormone receptors in the pituitary of ewes immunized actively with GnRHa (Ramakrishnappa et al 2005;Schneider et al 2006). Thus, it is not yet clear regarding the exact effects and mechanisms of GnRH analog on reproductive performance in animals (Bertschinger et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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Alarelin active immunization influences expression levels of GnRHR, FSHR and LHR proteins in the ovary and enhances follicular development in ewes

Wei

Chen

Gong

et al. 2013

Animal Science Journal

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We investigated the effects of gonadotropin releasing hormone (GnRH) agonist on expressions of GnRH receptor (GnRHR), follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) proteins in the ovaries and follicular development in the ewes. Forty-two pre-pubertal ewes were assigned to experimental groups 1 to 5 (EG-I to EG-V) and control group (CG). Ewes in EG-I, EG-II and EG-III were subcutaneously injected with 200, 300 or 400 μg alarelin antigens twice (on days 0 and 14), respectively. Ewes in EG-IV and EG-V were subcutaneously injected with 200 μg and 300 μg alarelin antigen four times (on days 0, 7, 14 and 21). Ewes in CG were subcutaneously injected with a solvent twice (on days 0 and 14). Serum concentrations of GnRH antibody in the EGs increased and were higher than (P<0.05) that of CG from day 14 to day 60. GnRH antibody concentrations in EG-IV and EG-V were higher than that in EG-I, EG-II and EG-III from days 35 to 45. Expressions of GnRHR protein in EG-IV and EG-V were lower than that in CG (P<0. 01). Expressions of FSHR and LHR proteins in EGs increased. Levels of FSHR and LHR proteins in EG-IV and EG-V (P<0.05) were higher than CG. Ovarian weights in EGs increased. Values of follicle vertical diameter, follicle transverse diameter, follicle wall thickness, follicle externatheca thickness and follicle internatheca thickness in EG-III and EG-V were greater than other groups. Primordial follicles and primary follicles developed quickly in alarelin-immunized animals. Secondary follicles and mature follicles became more abundant. Mitochondria, mitochondrial cristaes and cortical granules increased. Serum FSH concentrations of EGs remained higher than that in CG from days 28 to 70 (P<0.05). Alarelin immunization stimulated GnRH antibody production, suppressed expression of GnRHR protein, enhanced expressions of FSHR and LHR proteins in ovaries, promoted FSH secretion and thereby accelerated the development of ovaries and follicles in ewes.

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“…The analysis of plasma estradiol (E2) was performed by a modified 3 H-RIA after ethyl ether extraction of 100-μl samples in duplicate [18]. The antibody raised in rabbits and purified by chromatography was used at a titer of 1:55,000 together with [2,4,6, H]-estradiol from GE Healthcare (Freiburg, Germany).…”

Section: Estradiol-17β Assaymentioning

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...

show abstract

Endocrine, morphological, and cytological effects of a depot GnRH agonist in bovine

Cited by 10 publications

References 54 publications

Influence of unilateral ovariectomy performed before ovulation on ovarian function, steroid hormone levels and development of porcine fetuses

Influence of unilateral ovariectomy performed before ovulation on ovarian function, steroid hormone levels and development of porcine fetuses

Alarelin active immunization influences expression levels of GnRHR, FSHR and LHR proteins in the ovary and enhances follicular development in ewes

Endocrine Effects of GnRH Agonist Application to Early Pregnant Gilts

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