Cannabinoids and endocannabinoids negatively influence sperm functions. These substances have been demonstrated in many mammalian tissues, including male and female reproductive tracts, and previous studies have shown the presence of functional receptors for cannabinoids in human sperm. The present study, by means of RT-PCR and Western blot techniques, demonstrates that human sperm express the CB(1), but not CB(2), cannabinoid receptor (CB-R) subtype located in the head and middle piece of the sperm. The activation of this receptor by anandamide reduces sperm motility and inhibits capacitation-induced acrosome reaction. Activation of the CB(1)-R did not induce any variation in sperm intracellular calcium concentrations, but produced a rapid plasma membrane hyperpolarization that was reduced by the K(+) channel blocker tetraethylammonium. The effects of anandamide on human sperm motility were dependent on the reduction of sperm mitochondrial activity as determined by rhodamine 123 fluorescence. The specificity of anandamide effects in human sperm were confirmed by the effects of the CB(1)-R antagonist SR141716. These findings provide additional evidence that human sperm express functional CB(1)-R, the activation of which negatively influences important sperm functions, and suggest a possible role for the cannabinoid system in the pathogenesis of some forms of male infertility.

No external funding was sought or obtained for this study. No conflict of interest is declared.

Bone marrow-derived endothelial progenitor cells (EPCs) originate from haematopoietic stem cells in bone marrow and migrate into the peripheral circulation to promote endothelial repair and neovascularization. The number of circulating progenitor cells is reduced in patients with cardiovascular risk factor. The aim of our study was to determine the number of these cells in healthy patients and to evaluate the effect of Vardenfil, a phosphodiesterases-5 (PDE-5) inhibitor, in the number of circulating EPCs. In our study, we found a significant increase in the number of these cells after the drug administration.

Recent studies disclosed a cross talk between testis and bone. By the action of LH, Leydig cells are able to modulate bone metabolism through testosterone and insulin-like factor 3. Moreover, LH modulates the Leydig expression of CYP2R1, the key enzyme involved in vitamin D (Vit D) 25-hydroxylation. However, pathways regulating CYP2R1 expression have been poorly investigated. The cross talk from the bone to the testis of the vitamin D 25-hydroxylase CYP2R1 involves osteocalcin (OC), which is produced by the osteoblasts and stimulates the production of testosterone by the Leydig cells through its putative receptor GPRC6A, a cation-sensing G-protein-coupled receptor. The aim of this study was to investigate the possible action of OC on CYP2R1 expression and 25-hydroxy Vit D (25-OH Vit D) production in a mouse Leydig cell line (MA-10). After confirmation of the expression of GPRC6A by MA-10, we found that stimulation with either human chorionic gonadotropin or uncarboxylated-OC (ucOC) increases CYP2R1 protein expression in a dose-dependent manner and, in turn, increases the release of 25-OH Vit D in culture medium. This effect was abolished by receptor blockade with, respectively, anti-LH receptor and anti-GPRC6A antibodies. Moreover, both agonists converged to phosphorylation of Erk1/2 by a likely differential action on second messengers. Human chorionic gonadotropin induced slow "tonic" increase of intercellular calcium and accumulation of cAMP, whereas ucOC mainly induced phasic increase of cell calcium. Supporting these findings, we found that serum ucOC positively correlated with 25-OH Vit D levels in 40 overweight male patients and 21 controls. Altogether, our results suggest that OC contributes with LH to 25-OH Vit D production by Leydig cells.

These findings suggest that FNAC may be a simple and valid diagnostic parameter in non-obstructive azoospermic men and it may represent a valid positive prognostic parameter for sperm recovery at TESE.

Steroid hormones, beside their classical genomic mechanism of action, exert rapid, non genomic effects in different cell types. These effects are mediated by still poorly characterized plasma membrane receptors that appear to be distinct from the classic intracellular receptors. In the present study we evaluated the non genomic effects of estradiol (17bE 2 ) in human sperm and its effects on sperm stimulation by extracellular ATP, a potent activator of sperm acrosome reaction. In human sperm 17bE 2 induced a rapid increase of intracellular calcium (Ca 2+ ) concentrations dependent on an influx of Ca 2+ from the extracellular medium. The monitoring of the plasma membrane potential variations induced by 17bE 2 showed that this steroid induces a rapid plasma membrane hyperpolarization that was dependent on the presence of Ca 2+ in the extracellular medium since it was absent in Ca 2+ free-medium. When sperm were pre-incubated in the presence of the K + channel inhibitor tetra-ethylammonium, the 17bE 2 induced plasma membrane hyperpolarization was blunted suggesting the involvement of K + channels in the hyperpolarizing effects of 17bE 2 . Extracellular ATP induced a rapid plasma membrane depolarization followed by acrosome reaction. Sperm preincubation with 17bE 2 inhibited the effects of extracellular ATP on sperm plasma membrane potential variations and acrosome reaction. The effects of 17bE 2 were specific since its inactive steroisomer 17aE 2 was inactive. Furthermore the effects of 17bE 2 were not inhibited by tamoxifen, an antagonist of the classic 17bE 2 intracellular receptor.

In this study, we confirmed a steroidogenic role for d-Asp, in concert with hCG, on murine Leydig cells, which is mediated by an increase in StAR protein levels. In addition, we showed that the possible mechanism subtending the effect of d-Asp could rely on the modulation of LHR exposure on the cell membrane.