Uncarboxylated osteocalcin stimulates 25-hydroxy vitamin D production in Leydig cell line through a GPRC6a-dependent pathway.

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.

Role of zinc trafficking in male fertility: from germ to sperm.

Study Question: What are the dynamics of zinc (Zn) trafficking in sperm, at the testicular, epididymal and ejaculate levels?

Summary Answer: Zn transporters are peculiarly expressed in the cells of the germ line and Zn uptake is maximal at the post-epididymal phase, where Zn is involved in the regulation of sperm functions.

What Is Known Already: Zn is known to influence several phases of sperm life, from germ cell development to spermiation. Zn trafficking across the membrane is allowed by specific families of transporters known as the ZnTs, which are involved in effluent release, and the Zips, which mediate uptake.

Estradiol inhibits the effects of extracellular ATP in human sperm by a non genomic mechanism of action.

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 (17betaE(2)) in human sperm and its effects on sperm stimulation by extracellular ATP, a potent activator of sperm acrosome reaction.