OBJECTIVE Production of the appropriate pattern of gonadotrophin levels is crucial to proper functioning of the female reproductive system. We aimed to establish whether the pituitary has invariant secretory characteristics when isolated from in vivo controls. We aimed to obtain information during both the rising and declining phases of the gonadotrophin surge. DESIGN This study investigated ...

Previous studies from our laboratory, demonstrating that suppression of serum FSH by RU486 requires a high estrogen (E) background, suggested that E-inducible progesterone receptors play a role in the regulation of FSH secretion. We demonstrated further that the type II antiprogestin RU486 and the type I antiprogestin ZK98299 both suppressed the elevated serum FSH and FSHbeta messenger RNA leve...

To investigate a mode and a site of action of inhibin on FSH and LH secretion, in vivo and in vitro effects of porcine follicular fluid (PFF) on FSH and LH secretion were studied in male rats. PFF administered i.v. suppressed basal FSH levels for 1-8 hr, but did not alter LH levels. On the contrary, PFF given either 1 or 6 hr in advance, suppressed LH-RH stimulated LH responses as well as LH-RH...

Purpose To assess the ovarian reserve of patients with gestational trophoblastic neoplasia (GTN) treated with chemotherapy by evaluating serum anti-Müllerian hormone (AMH) and follicle-stimulating hormone (FSH) levels before, during, and after chemotherapy. Results The basal AMH level (mean: 3.98 ± 3.20 ng/mL) negatively correlated with age, while the basal FSH level (mean: 5.71 ± 9.69 mIU/mL...

BACKGROUND Previous studies suggest that elevated basal FSH concentrations are related to aneuploid pregnancies. However, there have been no prospective studies evaluating the incidence of aneuploidies in relation to basal FSH concentrations. Since the majority of aneuploid conceptions end in early pregnancy loss or abortion of a recognized pregnancy, these determinants are appropriate intermed...

In the present study, we started out to test whether the follicle-stimulating hormone (FSH)-activated p38 MAPK signaling cascade was involved in the regulation of steroidogenesis in granulosa cells (GCs). GCs were prepared from the ovaries of DES-treated immature rats and cultured in serum-free medium. Treatment of GCs with FSH (50 ng/ml) induced the phosphorylation of p38 MAPK rapidly with the...

OBJECTIVES It has been suggested that inhibin secretion is altered in women with the polycystic ovary syndrome (PCOS). However, the contribution of a preceding luteal phase has not been taken into account. The aim of the present study was to investigate whether progesterone in the context of a simulated luteal phase affects basal and FSH-induced inhibin secretion in women with PCOS and elevated...

BACKGROUND In men, the feedback of gonadotropins is regulated by estrogens that come from the aromatization of testosterone, but the relative contribution to the inhibition of LH and FSH secretion by the amount of locally produced estrogens within the hypothalamus and/or the pituitary, and the amount of circulating estrogens still remains unknown. OBJECTIVE In order to evaluate the effect of ...

Introduction: A favorable endometrium is the essential requirement for implantation. The aim of this study was to determine the predictive value of endometrial power Doppler ultrasonographic parameters in predicting the success of implantation in patients undergoing IVF and ICSI cycles. Methods: Seventy three patients aged<38 years with basal serum FSH level<12 , who had not more than two faile...

BACKGROUND A variety of indicators of potentially successful ovarian stimulation cycles are available, including biomarkers such as anti-Mullerian hormone. The aim of our study was to confirm the usefulness of serum anti-Mullerian hormone assay in predicting ovarian response and reproductive outcome in women eligible for ART cycles. MATERIALS Forty-six women undergoing ART cycles at the Centr...