Endocrine Abstracts

Kallmann syndrome (KS) combines hypogonadotropic hypogona dism and anosmia. Anosmia is related to the hypoplasia of the olfactory bulbs and tracts. Hypogonadism is due to deficiency in gonadotropin-releasing hormone (GnRH), and probably results from a failure of the embryonic migration of GnRH-synthesizing neurons. This is a genetically heterogeneous disease, which affects 1:8000 males and five times less females. Loss-of-function mutations in KAL1 and FGFR1 acco...

Reproduction in mammals is centrally regulated by neuroendocrine neurons scattered in the hypothalamus and secreting the decapeptide GnRH (gonadotropin releasing hormone). During development, GnRH-secreting neurons originate in the olfactory placode – at least in rodents – and migrate along olfactory nerves (the vomeronasal and the terminalis) to gain access to the forebrain and reach their final destinations in the hypothalamus. Defects in the migration of these neu...

Men with suppressed gonadotrophins, as induced by androgen-based contraceptive treatment, exhibit a 70% reduction in germ cell numbers (1). The mechanisms by which the germ cell populations are decreased are unknown. This study aimed to quantify the amount of germ cell apoptosis and proliferation and to identify the pathway(s) involved in gonadotrophin-induced germ cell loss in men. Testicular tissues from normal fertile men that received no treatment or testosterone (200 mg i...

Tyrosine phosphorylation of proteins is one of the main processes associated with the development of some specific functions of ejaculated human spermatozoa. Although this process, as well as the identity of the phosphorylated targets, has been well characterized, only few tyrosine kinases (TKs) have been identified so far. Moreover, their roles in regulating sperm functions are still unknown.In the present work, we report the presence and localization o...

Epididymis (epi) is a sex steroid-sensitive duct provided with spontaneous motility, allowing sperm transport. We previously demonstrated that human epi expresses a high abundance of mRNA for ER-alpha and ER-beta. We demonstrated that in epi estrogens up-regulate either oxytocin (OT) responsiveness, acting at the receptor level, and responsiveness to endothelin-1 (ET-1), another well-known stimulator of epididymal motility. However, we did not find any significant change eithe...

Objective: Anti-Müllerian hormone (AMH) has recently been evaluated as a marker for follicle reserve and as a new marker for ovarian function in women. In the male, it is produced in Sertoli cells (SC) in the testis. We evaluated serum levels of AMH as a marker of SC function and male fertility by comparing normo- and oligozoospermic men.Materials and methods: Serum levels of AMH were determined by enzyme immunoassay in two groups of men with normal...

There is a high prevalence of low testosterone levels in men with type 2 diabetes (DM2) and low testosterone predates the onset of DM2. Testosterone replacement therapy for hypogonadal men with DM2 improves insulin sensitivity and glycaemic control as well as reducing central obesity. This may lead to an increase in biochemical assessment of hypogonadism in men with DM2. Androgens and other steroid hormones are produced from cholesterol and it has been postulated that treatmen...