alexa Administration of a gonadotropin-releasing hormone antagonist to mares at different times during the luteal phase of the estrous cycle.
Diabetes & Endocrinology

Diabetes & Endocrinology

Journal of Steroids & Hormonal Science

Author(s): Evans MJ, Alexander SL, Irvine CH, Kitson NE, Taylor TB

Abstract Share this page

Abstract The GnRH antagonist cetrorelix was given during the early (Days 1-5), mid (Days 6-10 or 5-12) or for the entire (Days 1-16) luteal phase of mares to inhibit the secretion of FSH and LH (Day 0=ovulation). Frequent blood sampling from Day 6 to Day 14 was used to determine the precise time-course of the suppression (cetrorelix given Days 6-10). Cetrorelix treatment caused a decrease in FSH and LH concentrations by 8 and 16 h, respectively, and an obliteration of the response to exogenous GnRH given 24h after treatment onset. Treatment never suppressed gonadotropin concentrations to undetectable levels; e.g. frequent sampling showed that the nadirs reached in FSH and LH were 46.2±6\% and 33.1±11\%, respectively, of pre-treatment concentrations. Daily FSH concentrations were decreased in all treatment groups but daily LH concentrations were lower only when treatment commenced at the beginning of the luteal phase; progesterone concentrations depended on the time of cetrorelix administration, but the changes suggested a role for LH in corpus luteum function. The inter-ovulatory interval was longer than controls when cetrorelix was given in the mid- or for the entire luteal phase, but was unaffected by treatment in the early phase. Nevertheless, in all groups, FSH concentrations were higher (P<0.05 when compared to Day 0, subsequent ovulation) approximately 6-10 days before this next ovulation. This consistent relationship suggests a stringent requirement for a GnRH-induced elevation of FSH above a threshold at, but only at, this time; i.e. approximately 6-10 days before ovulation. Copyright © 2011 Elsevier B.V. All rights reserved. This article was published in Anim Reprod Sci and referenced in Journal of Steroids & Hormonal Science

Relevant Expert PPTs

Relevant Speaker PPTs

  • Rasha Mosa
    Effects of growth hormone secretagogue receptor agonist and antagonist in non-obese Type 2 Diabetes MKR mice
    PPT Version | PDF Version
  • Nisreen K Aref
    To compare serum leptin levels in obese women with polycystic ovary syndrome (PCOS) and normal ovulatory obese subjects in Saudi Arabia, and to evaluate the interrelationship between leptin concentration, sex hormones, and insulin resistance.
    PPT Version | PDF Version
  • George R. Bousfield
    Influence of Glycans on Biological Activities of Pituitary Gonadotropins: Follicle-Stimulating and Luteinizing Hormone
    PPT Version | PDF Version
  • P Krishnamoorthy
    Relationship of mineral and hormone profile of bovines with reproductive disorders in organized dairy farms in Karnataka and Tamil Nadu
    PPT Version | PDF Version
  • John Arnold D Souza
    Low levels of pesticides disrupt the pituitary- Gonadal hormone functions and reproductive functions in male rodent model
    PPT Version | PDF Version
  • Martha M Sklavos
    Anti-Müllerian hormone deficiency in females with inherited bone marrow failure syndromes
    PDF Version
  • Fuad Fares
    Developing long acting agonists and antagonists of glycoprotein hormones using gene fusion and gene transfer: From bench to clinics
    PPT Version | PDF Version
  • Paul J. Davis
    Nanotetrac targets the thyroid hormone receptor on integrin αvβ3 on tumor cells to promote apoptosis, disorder cell defense pathways and block angiogenesis
    PPT Version | PDF Version
  • A Martin Gerdes
    Wrong about β-blockers! Wrong about positive inotropes! Wrong about Thyroid Hormone treatment of Heart Failure?
    PDF Version

Recommended Conferences

Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version