Effect of number of receptors for gonadotropin-releasing hormone on the release of luteinizing hormone
1

Wise, Mark E.; Nieman, D.C.; Stewart, John M.; Nett, T. M.

doi:10.1095/biolreprod31.5.1007

Cited by 56 publications

(26 citation statements)

References 18 publications

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“…Pituitary gonadotropes produce and secrete LH, and the response of gonadotropes to GnRH is directly correlated with the number of GnRH receptors on the cell surface [29]. Expression of the GnRH receptor can be regulated by estradiol, progesterone, and GnRH itself [30][31][32].…”

Section: Discussionmentioning

confidence: 99%

Relationship of follicle size and concentrations of estradiol among cows exhibiting or not exhibiting estrus during a fixed-time AI protocol

Perry

Swanson

Larimore

et al. 2014

Domestic Animal Endocrinology

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a b s t r a c tCows exhibiting estrus near fixed-time artificial insemination (AI) had greater pregnancy success than cows not showing estrus. The objective of this study was to determine the relationship between follicle size and peak estradiol concentration between cows that did or did not exhibit estrus during a fixed-time AI protocol. Ovulation was synchronized in beef cows by applying the CO-Synch protocol [GnRH (100 mg) on day-9, prostaglandin F 2a (PGF2a; 25 mg) on day-2, and a second injection of GnRH 48 h after PGF 2a (day 0)] to both suckled (experiment 1) and nonsuckled (experiment 2) cows. Follicle size (day 0) and ovulation (day 2) was determined by ultrasonography. Blood samples were collected every 3 or 4 h beginning at the time of PGF 2a injection (0 h). Estrus was detected by visual observation with the aid of estrus-detection patches, and cows that ovulated were classified as exhibited estrus (n ¼ 46) or did not exhibit estrus (n ¼ 63). In both suckled and nonsuckled cows, there was a positive relationship between all cows (P < 0.05) and among those that exhibited estrus (P < 0.05) between follicle size and peak estradiol concentration, but no linear relationship (P > 0.50) between follicle size and peak estradiol concentration was observed among cows not exhibiting estrus. Cows that exhibited estrus had greater (P < 0.01) peak estradiol concentrations than cows that did not exhibit estrus. Suckled cows exhibiting standing estrus had greater (P < 0.001) preovulatory concentrations of estradiol beginning 6 h (replicate 1) or 4 h (replicate 2) after the injection of PGF 2a on day-2 compared with cows not exhibiting standing estrus. Nonsuckled cows exhibiting standing estrus had greater (P < 0.001) preovulatory concentrations of estradiol beginning at the injection of PGF 2a on day-2 compared with cows not exhibiting standing estrus. Furthermore, cows that exhibited estrus had an increased (P < 0.01) rate in the rise in concentrations of estradiol following the PGF 2a to peak estradiol than cows not exhibiting estrus. In summary, follicle diameter had a positive relationship with peak concentrations of estradiol, but only among cows that exhibited standing estrus, and estradiol increased earlier in cows that exhibited estrus compared with cows that did not.Ó 2014 Elsevier Inc. All rights reserved.Names are necessary to report factually on available data; however, neither South Dakota State University nor the USDA guarantees nor warrants the standard of the product, and use of names by South Dakota State University or the USDA implies no approval of the product to the exclusion of others that may also be suitable. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any ...

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Section: Discussionmentioning

confidence: 99%

Relationship of follicle size and concentrations of estradiol among cows exhibiting or not exhibiting estrus during a fixed-time AI protocol

Perry

Swanson

Larimore

et al. 2014

Domestic Animal Endocrinology

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“…The amount of LH secreted in response to the MBH release of GnRH depends on the number of GnRH receptors (R) present on the plasma membrane of the pituitary gonadotropes (239). In spontaneous ovulators, including rats (3), sheep (50), and humans (221), a single intravenous injection of GnRH increases pituitary sensitivity to subsequent pulses of GnRH, presumably by increasing GnRH-R numbers (e.g., 216).…”

Section: Role Of Pituitary Gnrh Receptors In the Preovulatory Lh Surgementioning

confidence: 99%

Neuroendocrine Regulation of GnRH Release in Induced Ovulators

Bakker

Baum

2000

Frontiers in Neuroendocrinology

180

135

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GnRH is the key neuropeptide controlling reproductive function in all vertebrate species. Two different neuroendocrine mechanisms have evolved among female mammals to regulate the mediobasal hypothalamic (MBH) release of GnRH leading to the preovulatory secretion of LH by the anterior pituitary gland. In females of spontaneously ovulating species, including rats, mice, guinea pigs, sheep, monkeys, and women, ovarian steroids secreted by maturing ovarian follicles induce a pulsatile pattern of GnRH release in the median eminence that, in turn, stimulates a preovulatory LH surge. In females of induced ovulating species, including rabbits, ferrets, cats, and camels, the preovulatory release of GnRH, and the resultant preovulatory LH surge, is induced by the receipt of genital somatosensory stimuli during mating. Induced ovulators generally do not show "spontaneous" steroid-induced LH surges during their reproductive cycles, suggesting that the positive feedback actions of steroid hormones on GnRH release are reduced or absent in these species. By contrast, mating-induced preovulatory surges occasionally occur in some spontaneously ovulating species. Most research in the field of GnRH neurobiology has been performed using spontaneous ovulators including rat, guinea pig, sheep, and rhesus monkey. This review summarizes the literature concerning the neuroendocrine mechanisms controlling GnRH biosynthesis and release in females of several induced ovulating species, and whenever possible it contrasts the results with those obtained for spontaneously ovulating species. It also considers the adaptive, evolutionary benefits and disadvantages of each type of ovulatory control mechanism. In females of induced ovulating species estradiol acts in the brain to induce aspects of proceptive and receptive sexual behavior. The primary mechanism involved in the preovulatory release of GnRH among induced ovulators involves the activation of midbrain and brainstem noradrenergic neurons in response to genital-somatosensory signals generated by receipt of an intromission from a male during mating. These noradrenergic neurons project to the MBH and, when activated, promote the release of GnRH from nerve terminals in the median eminence. In contrast to spontaneous ovulators, there is little evidence that endogenous opioid peptides normally inhibit MBH GnRH release among induced ovulators. Instead, the neural signals that induce a preovulatory LH surge in these species seem to be primarily excitatory. A complete understanding of the neuroendocrine control of ovulation will only be achieved in the future by comparative studies of several animal model systems in which mating-induced as well as spontaneous, hormonally stimulated activation of GnRH neurons drives the preovulatory LH surge. KEY WORDS: GnRH; MBH; induced ovulators; neuroendocrine regulation; preovulatory LH surge; spontaneous ovulators. © 2000 Academic Press Address correspondence and reprint requests to M. J. Baum at Dept. Biology, Boston University, 5 Cummington Street, Boston...

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“…GnRHR binds with affinity to GnRH on pituitary gonadotropes to stimulate release of the gonadotropic hormones; LH and FSH that in turn regulates production of gametes and gonadal hormones (Noar, 2009). The response of pituitary gonadotropes to GnRH correlates with the concentration of GNRH receptors (GnRHRs) on the cell surface (Wise et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

Identification of Single Nucleotide Polymorphism in GnRHR gene in Murrah bulls

Reen

Ramesha

Preeti

et al. 2018

IJAR

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The present study was undertaken with the objectives of molecular characterization and detection of genetic polymorphism in the GnRHR gene in Murrah bulls. Blood samples were collected from 109 Murrah bulls maintained at three different organized semen stations viz., Centralized Semen Collection Centre of Livestock Breeding and Training Centre, Dharwad; Nandini Sperm Station and State Livestock Breeding and Training Centre, Hessarghatta, Bengaluru, Karnataka, India. Genomic DNA was isolated from the blood samples within 24 hours of collection . Mutations were screened using Polymerase Chain Reaction -Single Stranded Conformational Polymorphism (PCR-SSCP) technique followed by Sanger Sequencing. PCR-SSCP method revealed similar band pattern within Murrah bulls. To confirm monomorphism in the studied population with respect to GnRHR gene, duplicate samples from each primer fragment were custom sequenced. PCR-SSCP and sequence analysis revealed monomorphism within the studied population that is coding region as well as exon-intron boundaries of GnRHR gene is highly conserved among Murrah bulls. However, a total of 28 Single Nucleotide variations (SNV's) have been found when compared with Bos Taurus reference sequence for GnRHR gene.

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Effect of number of receptors for gonadotropin-releasing hormone on the release of luteinizing hormone 1

Cited by 56 publications

References 18 publications

Relationship of follicle size and concentrations of estradiol among cows exhibiting or not exhibiting estrus during a fixed-time AI protocol

Relationship of follicle size and concentrations of estradiol among cows exhibiting or not exhibiting estrus during a fixed-time AI protocol

Neuroendocrine Regulation of GnRH Release in Induced Ovulators

Identification of Single Nucleotide Polymorphism in GnRHR gene in Murrah bulls

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