In species with external fertilization, the guanylate cyclase family is responsible for the long-distance interaction between gametes, as its activation allows sperm chemotaxis toward egg-derived substances, gamete encounter, and fertilization. In species with internal fertilization, guanylate cyclase-activating substances, which are secreted by several tissues in the genital tracts of both sex...

Human spermatozoa are quiescent in the male reproductive system and must undergo activation once introduced into the female reproductive tract. This process is known to require alkalinization of sperm cytoplasm, but the mechanism responsible for transmembrane proton extrusion has remained unknown because of the inability to measure membrane conductance in human sperm. Here, by successfully patc...

The kinetics of the creatine kinase (CK) reaction were studied in suspensions of quiescent and active, intact sea-urchin spermatozoa in artificial seawater, using 31P-NMR magnetization transfer. In inactive sperm, no CK-mediated exchange flux was detected, whereas in activated motile sperm, the forward pseudo-first-order rate constant was 0.13+/-0.04 s-1 at 10 degrees C, corresponding to a stea...

Plasma membrane hyperpolarization associated with activation of Ca2+-activated K+ channels plays an important role in sperm capacitation during fertilization. Although Slo3 (slowpoke homologue 3), together with the auxiliary γ2-subunit, LRRC52 (leucine-rich-repeat-containing 52), is known to mediate the pH-sensitive, sperm-specific K+ current KSper in mice, the molecular identity of this channe...

We previously reported the activation of adenylate cyclases from rat brain (Johnson, R. A., Awad, J. A., Jakobs, K. H., and Schultz, G., (1983) FEBS Lett. 152, 11-16) and from human platelets (Jakobs, K. H., Johnson, R. A., and Schultz, G. (1983) Biochim. Biophys. Acta 756, 369-375) by a factor derived from bovine sperm. In this report we describe the conditions for the extraction of the factor...

The calcium channel of sperm (CatSper) is essential for sperm hyperactivated motility and fertility. The steroid hormone progesterone activates CatSper of human sperm via binding to the serine hydrolase ABHD2. However, steroid specificity of ABHD2 has not been evaluated. Here, we explored whether steroid hormones to which human spermatozoa are exposed in the male and female genital tract influe...

Experiments were conducted to determine the effect of hypothermic 24 h storage on striped bass sperm cell plasma membrane integrity, free intracellular Ca(2+) ([Ca(2+)](i)), mitochondrial membrane potential (ΔΨ(m)), and reactive oxygen species (ROS) formation (oxidation of hydroethidine to ethidium) as determined by flow cytometry; motion activation and ATP concentration as determined by Lucife...

Sperm motility is an important parameter for success in intracytoplasmic sperm injection (ICSI) treatment. The sperm motility is due to its tail. If the sperm is not moving, it could be dead or alive. Normal live births have been obtained after ICSI with immotile sperm [1,2]. Various procedures have been applied to pick viable sperm for ICSI including, hypo-osmotic swelling (HOS) test [3], addi...