After the discovery of hypothalamic kisspeptin encoded by the Kiss1 gene, the central mechanism regulating gonadotropin-releasing hormone (GnRH) secretion, and hence gonadotropin secretion, is gradually being unraveled. This has increased our understanding of the central mechanism regulating puberty and subsequent reproductive performance in mammals. Recently, emerging evidence has indicated th...

OBJECTIVE To evaluate the relative importance of thyroid hormones and human chorionic gonadotropin in relation to the risk of gestational thyrotoxicosis in Saudi women living in Jeddah, Kingdom of Saudi Arabia. METHODS A prospective study was conducted on Saudi healthy pregnant women (N=406) at 12-15 weeks of gestation and compared with healthy non-pregnant controls (N=200). Maternal serum le...

Seasonally breeding birds detect environmental signals, such as light, temperature, food availability, and presence of mates to time reproduction. Hypothalamic neurons integrate external and internal signals, and regulate reproduction by releasing neurohormones to the pituitary gland. The pituitary gland synthesizes and releases gonadotropins which in turn act on the gonads to stimulate gametog...

IN 1906 Clevasseau classified tumours of the testis as teratomata, seminomata, interstitial cell tumours and adenomata. He noted the similarity between the seminoma and the epithelium of the seminal tubules, and considered that this type of tumour had its origin in the seminal epithelium. Nicholson (1907), Dew (1925), and Bell (1926) were in agreement with this theory. Since then numerous publi...

Luteinizing hormone/human chorionic gonadotropin stimulates progesterone biosynthesis in the corpus luteum by activating cyclic adenosine monophosphate/protein kinase A cascade. Recent studies have shown that cyclic adenosine monophosphate-mediated activation of protein kinase A interacts with the mammalian target of rapamycin signaling pathways. Furthermore, the use of mammalian target of rapa...

Since the discovery of gonadotropin-releasing hormone (GnRH) in mammals at the beginning of the 1970s, it was generally accepted that GnRH is the only hypothalamic neuropeptide regulating gonadotropin release in mammals and other vertebrates. In 2000, however, gonadotropin-inhibitory hormone (GnIH), a novel hypothalamic neuropeptide that actively inhibits gonadotropin release, was discovered in...

A case of a thirty-eight year old man with pseudohypoparathyroidism (PHP) type 1 associated with gonadotropin resistance and hypercalcitoninaemia was reported. The basal levels of the luteinizing hormone and follicle-stimulating hormone were elevated, and the responses to the luteinizing hormone-releasing hormone were exaggerated. The basal level of testosterone was normal, but the response to ...

there are currently ‎many different protocols in use for controlled ovarian hyperstimulation (coh), but the optimal method has ‎not yet been determined. to compare the outcome of coh using ‎clomiphene citrate (cc) versus cc plus human menopausal gonadotropin (hmg) in conjunction with intrauterine insemination (iui), we studied 117 infertile couples‎. iui with cc was used in 92 cycles ‎(group a)...

introduction: gonadotropin inhibitory hormone (gnih) is believed to be an inhibitor of gonadotropin releasing hormone (gnrh) secretion. the role of gnih in lactational inhibition of gonadotropin secretion is not well known therefore, the aim of the present study was to evaluate the effect of lactation on expression of gnih in these nuclei of lactating and non-lactating rats. methods: ten postpa...

conclusions our study showed that microrelin is as effective as diphereline in reducing psa and testosterone and can be recommended to initiate medical castration in patients with pc. results each group contained 40 patients. in group a, psa was reduced from 75.78 ± 72.43 ng/ml to 1.93 ± 1.40 ng/ml after 6 months and testosterone was reduced from 3.50 ± 1.12 nmol/l to 0.81 ± 0.05 nmol/l. there ...