Endocannabinoids and Kisspeptins: Two Modulators in Fight for the Regulation of GnRH Activity

The master system in the control of reproductive functions is the communication into the hypothalamus-pituitary-gonadal axis (HPG), whose main actor is the hypothalamic gonadotropin releasing hormone (GnRH). Such a decapeptide triggers the release of pituitary gonadotropins [Follicular Stimulating Hormone (FSH) and Luteinizing Hormone (LH)] which in turn reach the gonads, induce the biosynthesis of steroids (mainly testosterone in males and estradiol/progesterone in females) and of other non steroidal substances (i.e. activin, follistastin, inhibin) modulating the gametogenesis in both sexes. In the last decades, a significant upsurge of studies aimed to define seveal actors and mechanisms supporting reproductive activity. Ultra short, short and long feedback in HPG communication finely modulate reproduction. Nevertheless, this picture is still puzzling and the complete knowledge of the full process has to be unravelled

Fingerprint of dynamical charge/spin correlations in the tunneling spectra of colossal magnetoresistive manganites

We present temperature-dependent scanning tunneling spectroscopy measurements on $La_{1-x}Ca_{x}MO_{3}$ ($x\sim0.33$) films with different degrees of biaxial strain. A depletion in normalized conductance around the Fermi level is observed both above and below the insulator-to-metal transition temperature $T_{MI}$, for weakly as well as highly-strained films. This pseudogap-like depletion globally narrows on cooling. The zero-bias conductance decreases on cooling in the insulating phase, reaches a minimum close to $T_{MI}$ and increases on cooling in the metallic phase, following the trend of macroscopic conductivity. These results support a recently proposed scenario in which dynamical short-range antiferromagnetic/charge order correlations play a preeminent role in the transport properties of colossal magnetoresistive manganites [R. Yu \textit{et al}., Phys. Rev. B \textbf{77}, 214434 (2008)].Comment: 9 pages, 4 figure

Estrogens and Spermiogenesis: New Insights from Type 1 Cannabinoid Receptor Knockout Mice

Spermatogenesis is a complex mechanism which allows the production of male gametes; it consists of mitotic, meiotic, and differentiation phases. Spermiogenesis is the terminal differentiation process during which haploid round spermatids undergo several biochemical and morphological changes, including extensive remodelling of chromatin and nuclear shape. Spermiogenesis is under control of endocrine, paracrine, and autocrine factors, like gonadotropins and testosterone. More recently, emerging pieces of evidence are suggesting that, among these factors, estrogens may have a role. To date, this is a matter of debate and concern because of the agonistic and antagonistic estrogenic effects that environmental chemicals may have on animal and human with damaging outcome on fertility. In this review, we summarize data which fuel this debate, with a particular attention to our recent results, obtained using type 1 cannabinoid receptor knockout male mice as animal model

Migration of phthalates, alkylphenols, bisphenol A and di(2-ethylhexyl)adipate from food packaging

The migration of plastic components or additives from packaging to food can produce a risk for human health, in fact many of these plasticizers and additives are "Endocrine Distruptors", such as phthalates (PAEs), alkylphenols (APs), 2,2-bis(4-hydroxyphenyl)propane (bisphenol A or BPA) and di(2-ethylhexyl) adipate (DENA). The evaluation of some PAEs, some APs, BPA and DEHA levels in common food packaging (oil and natural tuna cans, marmalade cap, yogurt packaging, polystyrene dish, teat, bread bag, film, baby's bottle, aseptic plastic laminate paperboard carton and plastic wine top) was carried out by migration tests. Furthermore to evaluate the potential migration of plasticizers and additives from plastic wine tops, two extraction methods were used, one through incubation at 40 degrees C for 10 days and one by ultrasounds extraction. The simulants employed were distilled water, acetic acid at 3%, ethanol at 15% for wine top. The food simulant was extracted by solid phase extraction (SPE) and analyzed by GC-MS. Comparing these results with EU restrictions all samples showed contaminant migration lower than SML and OML established. Finally, about the comparison of two extraction methods, the extraction carried out for 10 days at 40 degrees C may be better than the other one in order to detect all compounds. (C) 2012 Elsevier Ltd. All rights reserved

Intra-Testicular Signals Regulate Germ Cell Progression and Production of Qualitatively Mature Spermatozoa in Vertebrates

Spermatogenesis, a highly conserved process in vertebrates, is mainly under the hypothalamic-pituitary control, being regulated by the secretion of pituitary gonadotropins, FSH and LH, in response to stimulation exerted by Gonadotropin Releasing Hormone (GnRH) from hypothalamic neurons. At testicular level, gonadotropins bind specific receptors located on the somatic cells regulating the production of steroids and factors necessary to ensure a correct spermatogenesis. Indeed, besides the endocrine route, a complex network of cell-to-cell communications regulates germ cell progression, and a combination of endocrine and intragonadal signals sustains the production of high quality mature spermatozoa. In this review we focus on the recent advances in the area of the intragonadal signals supporting sperm development.<br/