To examine the effect of diet on luteinizing hormone (LH) secretion, basal and luteinizing hormone releasing hormone (LHRH)-induced LH release was compared in intact or castrated-estradiol-17 beta implanted Finn-Dorset lambs. Ten to 12 wk old ram (n = 20) and ewe lambs (n = 20) were maintained under a 8L:16D photoperiod and fed for high (HG, 163 to 168 g/d) or low (LG, 76 to 103 g/d) rates of g...

BACKGROUND Oligoasthenoteratozoospermia (OAT) syndrome is the most frequently seen phenotype in male infertility. Spermatogenesis relies closely on hormone regulation. The aim of this study was to assess the correlation between hormone profile and semen parameters in infertile men with idiopathic or varicocele-related OAT syndrome. We tried to illustrate the correlative factors for better semen...

BACKGROUND There is no consensus on the exact parameters that define the LH surge for natural cycle frozen-thawed embryo transfers (NC-FET). Accurately determining the LH surge would affect the timing, and subsequently the success rates, of embryo transfer. Therefore, the aim of this study was to delineate the optimal levels and relationship for luteinizing hormone (LH) and estradiol in an effo...

In women, progesterone suppresses luteinizing hormone (LH) (gonadotropin-releasing hormone) pulse frequency, but how rapidly this occurs is unknown. In estradiol-pretreated women in the late follicular phase, progesterone administration at 1800 did not slow sleep-associated LH pulse frequency. However, mechanisms controlling LH pulse frequency may differ according to sleep status; and we thus h...

CONTEXT Recent evidence suggests that ghrelin exerts a negative modulation on the gonadal axis. Ghrelin was reported to suppress LH secretion in both animal and human models. Moreover, acylated ghrelin (AG) also decreases the LH responsiveness to GnRH in vitro. OBJECTIVE The objective of the study was to evaluate the effects of AG infusion on spontaneous and stimulated gonadotropin secretion....

Although luteinizing hormone (LH) is known to down-regulate its own receptor in several gonadal cell types, the mechanisms underlying this process are poorly understood. To elucidate these mechanisms we have examined the role of cAMP and progesterone in LH-stimulated down-regulation of the LH receptor, using cultured granulosa cells as a model. LH receptors were induced by culturing the cells w...

Introduction Uveal melanoma (UM) is the most common primary intraocular malignancy with very poor prognosis. Conventional chemotherapy only rarely prolongs the survival, therefore patients require novel treatment modalities. The discovery of specific receptors for hypothalamic hormones on cancer cells has led to the development of radiolabeled and cytotoxic hormone analogs. Materials and meth...

Download pose: In addition to their expression on pituitary cells, receptors for luteinizing hormone-releasing ne (LH-RH) are found on most prostate cancer cells. These tumoral LH-RH receptors mediate the cytotoxic effects of LH-RH analogs and are potential therapeutic targets. Although pituitary LH-RH ors are downregulated following prolonged exposure to LH-RH agonists, there is no evidence th...

CONTEXT In women with polycystic ovarian syndrome (PCOS), the relationship of insulin to LH secretion and responses to GnRH remains unresolved. A rigorous analytical examination of this relationship has not been performed. OBJECTIVE Our objective was to determine the relationship of basal LH secretion and responses to GnRH, insulin, and other endocrine variables in normal and PCOS women. DE...