Gonadotropin-releasing hormone (GnRH) neurons form the final common pathway for central control of fertility. Regulation of GnRH neurons by long-loop gonadal steroid feedback through steroid receptor-expressing afferents such as GABAergic neurons is well studied. Recently, local central feedback circuits regulating GnRH neurons were identified. GnRH neuronal depolarization induces short-term in...

GnRH antagonists induce a rapid decrease in LH and FSH, preventing and interrupting LH surges. Their properties do not require a desensitization period, and this allows their use in the late follicular phase. GnRH antagonists could replace GnRH agonists in controlled ovarian stimulation without their side-effects and their long desensitization period. Two protocols for assisted reproduction tec...

background: premature luteinization during in vitro fertilization was commonly happened before the introduction of gnrh analogues. high level of unwanted progesterone is associated with adverse pregnancy outcome and is thought to be induced by inappropriate lh elevation.objective: to evaluate the progesterone level on the day of human chorionic gonadotropin (hcg) triggering in gnrh agonist and ...

AIM To provide results of the use of estradiol pretreatment in a combination of an ultrashort gonadotropin-releasing hormone (GnRH) agonist and antagonist protocol, in an attempt to improve the clinical outcomes in "poor responders", according to the Bologna criteria, undergoing in vitro fertilization (IVF). PATIENTS AND METHODS We applied estradiol pretreatment to 20 participants before the ...

In an attempt to resolve the apparent controversy in the observed effects of gonadotrophin-releasing hormone (GnRH) analogues on the ovary, conventional binding studies were conducted with a GnRH agonist and an antagonist in various ovarian tissues to demonstrate possible GnRH receptor binding. In human luteinized granulosa cells derived from unstimulated in-vitro fertilization cycles, high aff...

BACKGROUND The purpose of the study was to determine if the effect of llama OIF on LH secretion is mediated by stimulation of the hypothalamus or pituitary gland. METHODS Using a 2-by-2 factorial design to examine the effects of OIF vs GnRH with or without a GnRH antagonist, llamas with a growing ovarian follicle greater than or equal to 8 mm were assigned randomly to four groups (n = 7 per g...

STUDY QUESTION Do high-risk patients who develop severe early ovarian hyperstimulation syndrome (OHSS) and receive low-dose GnRH antagonist in the luteal phase have lower live birth rates compared with high-risk patients who do not develop severe early OHSS and do not receive GnRH antagonist in the luteal phase? SUMMARY ANSWER Low-dose luteal GnRH antagonist administration in women with sever...

BACKGROUND Bisphenol A (BPA) is a component of polycarbonate plastics, epoxy resins, and polystyrene and is found in many products. Several reports have revealed potent in vivo effects, because BPA acts as an estrogen agonist and/or antagonist and as an androgen and thyroid hormone antagonist. OBJECTIVES We analyzed the effects of neonatal exposure to BPA on the reproductive axis of female Sp...