Gonadotropins (follicle-stimulating hormone (FSH), luteinizing hormone, and human chorionic gonadotropin) and beta-adrenergic agonists have been shown to stimulate expression of the proopiomelanocortin (POMC) gene in ovarian granulosa cells. The current studies investigate the intracellular mechanisms by which gonadotropins regulate gene expression. Primary cultures of rat granulosa cells were ...

Purpose. To improve success of in vitro fertilization (IVF), assisted reproductive technology (ART) experts addressed four questions. What is optimum oocytes number leading to highest live birth rate (LBR)? Are cohort size and embryo quality correlated? Does gonadotropin type affect oocyte yield? Should "freeze-all" policy be adopted in cycles with progesterone >1.5 ng/mL on day of human chorio...

Follicular maturational competence and ovulatory competence in teleost fish refer to the ability of the ovarian follicle to undergo final oocyte maturation and ovulation, respectively, in response to gonadotropin stimulation and other external cues. Some gene products related to competence acquisition are likely synthesized during vitellogenic growth, as these follicles gain in vivo responsiven...

In PCOS women with insulin resistance, hyperinsulinemia may contribute to inappropriate gonadotropin secretion. To determine whether insulin influences gonadotropin release in PCOS, pulsatile LH secretion and gonadotropin responses to GnRH were evaluated before (phase 1) and during (phase 2) insulin infusion. In phase 1, 11 PCOS and 9 normal women on separate days underwent 1) frequent blood sa...

Introduction: The role of estrogen in the stimulation of gonadotropin-releasing hormone (GnRH) neurons is clear. These neurons do not express estrogen alpha receptors, so other mediator neurons should be present to transmit the positive feedback effect of estrogen to the GnRH neurons. Kisspeptin neurons have an important role in the stimulation of GnRH neurons, so they can be the mediator of...

Gonadotropin-releasing hormone in Cyprinidae as in other Vertebrates functions as a brain signal which stimulates the secretion of luteinizing hormone from the pituitary gland. Two forms of gonadotropin-releasing hormone have been identified in cyprinids, chicken gonadotropin-releasing hormone II and salmon gonadotropinreleasing hormone. Hypohysiotropic functions are fulfilled mainly by salmon ...

BACKGROUND Gonadotropin-releasing hormone (GnRH) analogues are used routinely to prevent a premature luteinizing hormone (LH) surge in women undergoing assisted reproductive technology (ART) treatments. In contrast to GnRH agonists, antagonists produce rapid and reversible suppression of LH with no initial flare effect. OBJECTIVE To review the role of cetrorelix, the first GnRH antagonist app...

Background To compare a flexible, multi-dose GnRH antagonist protocol with a long GnRH .agonist protocol in poor respo MaterialsAndMethods A randomized clinical trial of 70 poor responder patients (35 patients in GnRH antagonist protocol and 35 patients in long GnRH agonist protocol) was performed at Royan Institute, Tehran, Iran. Both groups were given a fixed dose of human menopausal gonadotr...