Neuropeptide Y (NPY) stimulates the release of GnRH in an estrogen (E2)-dependent manner, which is important in generating preovulatory GnRH surges. We tested the hypothesis that E2 up-regulates NPY's actions by stimulating NPY Y1 receptor (Y1r) gene expression through a mechanism mediated by E2's ability to induce progesterone (P) receptors (PRs). In initial experiments, a specific Y1r antagon...

OBJECTIVE To investigate the role of interleukin-1beta (IL-1beta) in regulating GnRH mRNA expression in cultured human endometrial stromal cells using a modified semiquantitative competitive reverse transcription and polymerase chain reaction (PCR). DESIGN A controlled study. SETTING Clinical and academic research setting in a university medical center. PATIENT(S) Women undergoing hystere...

OBJECTIVE Luteal phase is defective in in vitro fertilization (IVF) cycles, and many regimens were tried for the very best luteal phase support (LPS). Gonadotropin releasing hormone (GnRH) agonist use, which was administered as an adjunct to the luteal phase support in IVF cycles, was suggested to improve pregnancy outcome measures in certain randomized studies. We analyzed the effects of addit...

We previously showed that exogenous testosterone (T) inhibited GnRH-antagonist-stimulated spermatogenic recovery in irradiated rats through an androgen-receptor-mediated action. In the present study, we tested whether the inhibition is attributable to T, a specific androgenic metabolite of T, or a general property of androgens in this system. In addition, we also tested whether estradiol-17beta...

Background: The objective of this study is to evaluate the progesterone level (P Level) on the day of HCG triggering in GnRh agonist and antagonist protocols, and its correlation with clinical pregnancy rate and miscarriage rate. Premature luteinization during in vitro fertilization (IVF) was commonly happened before the introduction of GnRh analogues. High level of unwanted progesterone that i...

Objective This retrospective study compared the effect of the luteal phase ovarian stimulation protocol (LP group) with the gonadotrophin-releasing hormone (GnRH) antagonist protocol (AN group) in women with poor ovarian responses. Methods Ovarian stimulation was initiated with 225 IU of human gonadotrophin (hMG) daily. When the dominant follicle diameter exceeded 13 mm, 0.25 mg of a GnRH antag...

Atresia, a degenerative process through which many follicles are removed from the growing pool, involves apoptotic changes in the follicular granulosa cells. To identify histochemical markers of early stages of atresia, an in-vivo rat model was used which allowed the study of atresia of pre-ovulatory follicles in a synchronized and chronological order. By blocking the pre-ovulatory luteinizing ...

BACKGROUND Our objective was to evaluate the effectiveness of clomiphene citrate (CC) vs. letrozole (L) plus human menopausal gonadotropin (hMG) in gonadotropin releasing hormone (GnRH) antagonist protocol in poor prognosis women with previous failed ovarian stimulation undergoing intracytoplasmic sperm injection (ICSI). MATERIALS AND METHODS This retrospective cohort study included cycles wi...

Glucose regulates energy homeostasis and reproductive function within the hypothalamus. The underlying mechanisms responsible for glucose regulation of GnRH gene transcription were investigated using a novel murine immortalized, adult-derived hypothalamic cell line, mHypoA-GnRH/GFP. Analysis of GnRH mRNA synthesis and secretion following agonist treatment demonstrated that the mHypoA-GnRH/GFP c...

BACKGROUND The role of progesterone for luteal support in stimulated cycles for IVF is well established. However, controversy still surrounds the benefit of additional supplementation with estradiol (E2) in GnRH agonist (GnRHa) cycles, while no such data are available for GnRH antagonists. The aim of this randomized controlled trial (RCT) was to compare ongoing pregnancy rates in patients stimu...