The agonist-bound gonadotropin-releasing hormone (GnRH) receptor engages several distinct signaling cascades, and it has recently been proposed that coupling of a single type of receptor to multiple G proteins (G(q), G(s), and G(i)) is responsible for this behavior. GnRH-dependent signaling was studied in gonadotropic alphaT3-1 cells endogenously expressing the murine receptor and in CHO-K1 (CH...

In this paper a mathematical model is developed based on current biological concepts of the lamprey GnRH-III involved in LH and FSH concentration . The physiologic role played by GnRH-III on gonadotropin secretion in mammalian species is controversial. Although GnRH-III is a weak GnRH agonist, early research in mammalian species suggested that GnRH-III can selectively stimulate the secretion of...

The management of poor responders in IVF cycles is extremely controversial due to their inadequate response to controlled ovarian hyperstimulation.. A low ovarian response may be idiopathic or may be associated with many different factors including age, diminished ovarian reserve, endometriosis and prior ovarian surgery, and a reported incidence 9-24% of IVF patients. Several strategies have be...

BACKGROUND Gonadotrophin-releasing hormone (GnRH) agonist is used for controlling ovarian stimulation in assisted reproductive technology (ART) cycles which has some benefits. OBJECTIVE To compare the efficacy of two different formulations of GnRH agonist: short-acting and long-acting, for ART protocols. MATERIALS AND METHODS In a prospective randomized study, one hundred women who underwen...

OBJECTIVE There are no long-term medical treatments for uterine fibroids, and non-invasive biomarkers are needed to evaluate novel therapeutic interventions. The aim of this study was to determine whether serial dynamic contrast-enhanced MRI (DCE-MRI) and magnetization transfer MRI (MT-MRI) are able to detect changes that accompany volume reduction in patients administered GnRH analogue drugs, ...

OBJECTIVE To report two cases with GnRH agonist triggering and a freeze-all approach in a GnRH antagonist protocol resulting in the development of severe ovarian hyperstimulation syndrome (OHSS), requiring hospitalization and peritoneal drainage. DESIGN Two case reports. SETTING A tertiary referral center and an obstetrics and gynecology department of a hospital. PATIENT(S) Case 1 and cas...

Objectives: To evaluate the efficacy of alteration from gonadotropin-releasing hormone (GnRH) agonist to antagonist in patients with castration-resistant prostate cancer (CRPC). Methods: Fourteen patients with CRPC were switched from GnRH agonist to GnRH antagonist. CRPC was defined as 3 consecutive rises of PSA values under androgen deprivation therapy despite a testosterone level at the castr...

Replacing GnRH agonist cotreatment for the prevention of a premature rise in LH during ovarian stimulation for in vitro fertilization (IVF) by the late follicular phase administration of GnRH antagonist may render supplementation of the luteal phase redundant, because of the known rapid recovery of pituitary function after antagonist cessation. This randomized two-center study was performed to ...

BACKGROUND A bolus dose of GnRH agonist can substitute for hCG as a trigger for the resumption of meiosis in ovarian stimulation with GnRH antagonists, which has been suggested to reduce the risk of ovarian hyperstimulation syndrome (OHSS). As the efficacy of this measure in fresh embryo transfer (ET) cycles is unclear, we evaluated a new clinical concept of GnRH-agonist triggering. METHODS I...