Background: Mammalian sperm must undergo a process termed capacitation to become competent to fertilize an egg. Capacitation renders the sperm competent by priming the cells to undergo a rapid exocytotic event called acrosomal exocytosis that is stimulated by the zona pellucida (ZP) of the egg or progesterone. Over the years, several biochemical events have been associated with the capacitation...

W hen females are sexually promiscuous, the ejaculates of different males may compete for the fertilization of a set of ova, a process known as sperm competition. In internally fertilizing species, potential for sperm competition occurs whenever the ejaculates of different males cooccur in the female reproductive tract at the time of ovulation. Sperm competition is now recognized as a powerful ...

BACKGROUND Spermatozoa acquire the ability to fertilize an oocyte when they become capacitated. Capacitation takes place when sperm pass through the female reproductive tract, interacting with female fluids. Both tyrosine phosphorylation of sperm proteins and the ability to respond to acrosome reaction (AR) inducers have been associated with sperm capacitation. Recent data indicate that conditi...

Sperm capacitation is a complex and indispensable physiological process that spermatozoa must undergo in order to acquire fertilization capability. Spermatozoa from several mammalian species, including mice, exhibit a capacitation-associated plasma membrane hyperpolarization, which is necessary for the acrosome reaction to occur. Despite its importance, this hyperpolarization event has not been...

Semenogelin (Sg), the major protein of the human semen coagulum, is present at high concentrations in seminal vesicle secretions. It is degraded by the prostate-specific antigen (PSA) to generate peptides of various biological activities that were found on and inside spermatozoa. Our aim was to determine the effect of Sg on capacitation, which is the series of transformations that spermatozoa m...

Sperm capacitation involves an increase in intracellular Ca(2+) concentration as well as in protein kinase A (PKA)-dependent protein tyrosine (Tyr) phosphorylation. Interestingly, in humans, a decrease in extracellular Ca(2+) concentration ([Ca(2+)]e) during capacitation induces an increase in Tyr phosphorylation indicating the complexity of Ca(2+) signaling during this process. In view of this...

Ejaculated mammalian sperm must undergo a maturation process called capacitation before they are able to fertilize an egg. Several studies have suggested a role for members of the secreted phospholipase A2 (sPLA2) family in capacitation, acrosome reaction (AR), and fertilization, but the molecular nature of these enzymes and their specific roles have remained elusive. Here, we have demonstrated...

BACKGROUND Mammalian spermatozoa have been shown to have beta(1,2,3)- and alpha(2A)-adrenergic receptors, the former functioning only in uncapacitated spermatozoa and the latter only in capacitated cells. Cathine, an amphetamine-related metabolite of a compound found in Catha edulis leaves, accelerates capacitation and inhibits spontaneous acrosome loss by regulating cAMP production. This study...

BACKGROUND Mammalian spermatozoa acquire their full fertilizing ability (so called capacitation) within the female genital tract, where they are progressively exposed to inverse gradients of inhibiting and stimulating molecules. METHODOLOGY/PRINCIPAL FINDINGS In the present research, the effect on this process of anandamide, an endocannabinoid that can either activate or inhibit cannabinoid r...

Before fertilization, spermatozoa must undergo a process called capacitation in order to fulfill their fertilization potential. This includes series of structural, biochemical, and functional changes before subsequent acrosome reaction fusion with the oocyte. However, low temperatures during cryopreservation may induce premature activation capacitation-like changes, also known as cryocapacitati...