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CONTEXT The cause of declining testosterone (T) in aging men and their relationships with risk factors are unclear. OBJECTIVE The objective of the study was to investigate the relationships between lifestyle and health with reproductive hormones in aging men. DESIGN This was a baseline cross-sectional survey on 3200 community-dwelling men aged 40-79 yr(More)
Progesterone induced a rapid, long-lasting, dose-dependent increase of intracellular free calcium concentration ([Ca2+]i) in human sperm capacitated overnight. This effect was not counteracted by the cytosolic progesterone receptor antagonist RU486 (1 mumol/L) nor by the GABA-A receptor antagonists bicuculline (10 mumol/L) and picrotoxin (50 mumol/L). Also,(More)
The penis remains in a hypo-oxygenated, flaccid state for a large majority of the time. In this study, we investigated the effect of changing oxygen tension on the expression and functional activity of endothelin-1 (ET-1) receptors in the penis. Experiments were performed in rabbit and human corpora cavernosa (CC) as well as in human fetal penile tissue and(More)
By real-time RT-PCR and Western blot analysis, we found that phosphodiesterase type 5 (PDE5) mRNA and protein abundance was several fold higher in human male than in female reproductive tracts. The highest mRNA level (>1 x 10(7) molecules/microg total RNA) was detected in human corpora cavernosa (CC), where PDE5 protein was immunolocalized in both muscular(More)
Since 1995, thanks to a large number of studies, Y chromosome microdeletion screening has become part of the routine diagnostic work-up of severe male factor infertility. Many initial contradictory issues such as variability in deletion frequency, markers to be tested, presence of deletions in 'fertile' men, and genotype-phenotype correlation has been(More)
In this study we have investigated responsiveness to progesterone in spermatozoa from a group of unselected male partners of couples undergoing in-vitro fertilization (IVF). We evaluated progesterone-stimulated intracellular Ca2+ ([Ca2+]i) and percentage increase in acrosome reaction in the same sperm sample used for oocyte inseminations. [Ca2+]i was(More)
BACKGROUND Protein tyrosine phosphorylation is one of the main processes associated with sperm activation. Although this process and its targets have been well characterized, only few tyrosine kinases have been identified so far and their roles in spermatozoa are still largely unknown. In this study, we report the presence and localization of Src kinase in(More)
The presence of functional nongenomic progesterone (P) receptors in human spermatozoa has been investigated by equilibrium binding studies in intact spermatozoa, ligand blot and Western blot analysis of sperm lysates, as well as determination of the effects of the steroid on sperm intracellular Ca2+ concentrations. Binding experiments were performed using(More)
We report for the first time that penile smooth muscle cells (SMC) not only respond to, but also synthesize, endothelin-1 (ET-1), one of the main regulators of SMC activity. Immunohistochemical studies indicated that, beside endothelial cells (EC), SMC of the human adult and fetal penis also express ET-1 and its converting enzyme, ECE-1. Accordingly,(More)