Protein kinase C (PKC) is localized in the equatorial segment and the principal piece of the tail of spermatozoa. Activator of PKC results in increasing flagellar motility of sperm that is blocked by PKC inhibitors such as staurosporine. A good correlation (r = 0.9, P < 0.001) is found between the content of PKC in sperm and sperm motility. Zona pellucida (ZP) stimulates the spermatozoa binding the acrosome reaction resulting in the release of hydrolytic enzymes and in the exposure of new membrane domains. ZP binding to receptors in the plasma membrane can regulate adenyl cyclase (AC) leading to elevation of cAMP and protein kinase A (PKA) activation. The PKA activates a voltage-dependent Ca2+ channel in the outer acrosomal membrane which releases Ca2+ from the interior of the acrosome to the cytosol. Activation of the PLC resulted from the rise in Ca2+ hydrolyze phosphatidyl inositol bisphosphate. The product activate PCK to open a voltage-dependent Ca2+ channel (L) in the plasma membrane, leading to the second (II) Ca2+ higher increase which result in membrane fusion and acrosome reaction. It is proposed that PKC would be involved in the regulation of motility and acrosome reaction of sperm.
Acrosome Reaction ; physiology ; Humans ; Male ; Protein Kinase C ; metabolism ; Sperm Motility ; physiology ; Spermatozoa ; enzymology ; physiology

Zona pellucida (ZP) plays a key role in the recognition, combination and penetration of sperms and oocytes, the prevention of multiple impregnation, the protection of embryos, and so on. The paper reviews the constitution, molecular structure, biological function and application of zona pellucida in male fertilization.
Acrosome Reaction ; physiology ; Animals ; Female ; Fertility ; physiology ; Humans ; Male ; Mice ; Molecular Structure ; Zona Pellucida ; chemistry ; physiology

Phospholipase C (PLC) is a key enzyme in phosphatidyl inositol turnover during signal transduction. The 12 mammalian PLC isozymes identified to date can be divided into five subtypes, beta-type, gamma-type, delta-type, epsilon-type and zeta-type, with extensive difference in structure, regulatory mechanism and tissue distribution. PLC plays important roles not only in sperm acrosome reaction but also in egg activation. The present studies are reviewed on the structure, regulation and function of PLC, especially its function in male reproduction, including triggering Ca2+ oscillations in eggs to activate the eggs and helping embryo development. And the prospect of the clinical application of PLC is discussed.
Acrosome Reaction ; Animals ; Calcium Signaling ; Humans ; Reproduction ; physiology ; Signal Transduction ; Type C Phospholipases ; chemistry ; physiology

Human sperm-egg recognition, adhesion and fusion are key steps in the whole reproductive process. Some abnormalities in human gamete interaction have been shown to be due to defects in the sperm, others attributed to defects in the zona pellucida (ZP) and the egg plasma membrane. This paper reviews the molecular basis and molecular mechanisms of human sperm-egg interaction. More and more advances in the studies of these aspects are shown to be of significant value to the diagnosis and treatment of infertility as well as to the development of assisted reproductive techniques.
Acrosome Reaction ; physiology ; Female ; Humans ; Infertility, Male ; physiopathology ; Male ; Sperm-Ovum Interactions ; physiology ; Zona Pellucida

This article reviews the advances in the studies of A-kinase anchor proteins (AKAPs) in sperm, including their classification, structure and mechanism. The influence of AKAPs that are involved on sperm mobility and acrosome reaction is emphasized. We hope it could play a directive role in the studies of AKAPs that are involved in regulating sperm mobility and acrosome reaction.
A Kinase Anchor Proteins ; Acrosome Reaction ; physiology ; Adaptor Proteins, Signal Transducing ; chemistry ; physiology ; Animals ; Cattle ; Humans ; Male ; Mice ; Sperm Motility ; physiology

AIMTo develop a method for assessing sperm function by measuring released acrosin activity during the acrosome reaction (AR).

METHODSHuman semen samples were obtained from 24 healthy donors with proven fertility after 3-7 days of sexual abstinence. After collection, samples were liquefied for 30 min at room temperature. Standard semen parameters were evaluated according to World Health Organization (WHO) criteria. Calcium ionophore A23187 and progesterone (P4) were used to stimulate the sperm to undergo AR. After treatment, sperm were incubated with the supravital dye Hoechst33258, fixed in a glutaraldehyde-phosphate-buffered saline solution, and the acrosomal status was determined by fluorescence microscopy with fluorescein isothiocyanate-labeled Pisum sativum agglutinin (FITC-PSA). The percentage of sperm undergoing AR (AR%) was compared to sperm acrosin activities as assessed by spectrocolorimetry. The correlation between AR% and acrosin activity was determined by statistical analysis.

RESULTSThe AR% and released acrosin activity were both markedly increased with A23187 and P4 stimulation. Sperm motility and viability were significantly higher after stimulation with P4 versus stimulation with A23187 (P < 0.001). There was a significant positive correlation between released acrosin activity and AR% determined by FITC-PSA staining (r=0.916, P < 0.001).

CONCLUSIONSpectrocolorimetric measurement of released acrosin activity might serve as a reasonable alternative method to evaluate AR.

Acrosin ; physiology ; Acrosome Reaction ; Adult ; China ; Humans ; Male ; Progesterone ; pharmacology ; Semen ; drug effects ; physiology ; Sperm Motility ; drug effects ; physiology

Epididymal maturation is associated with the activation of a cAMP-induced tyrosine phosphorylation cascade, which is ultimately associated with the expression of capacitation-dependent sperm functions, such as hyperactivated movement and acrosomal exocytosis. As spermatozoa progress through the epididymis they first acquire the capacity to phosphorylate tyrosine on targets on the principal piece, followed by the midpiece. By the time these cells have reached the cauda epididymidis they can phosphorylate the entire tail from neck to endpiece. This particular pattern of phosphorylation is associated with the ontogeny of fully functional spermatozoa that are capable of fertilizing the oocyte. Proteomic analyses indicate that this change is associated with the phosphorylation of several mitochondrial proteins, creation of a mitochondrial membrane potential and activation of mitochondrial free radical generation. At least in rodent species, activation of sperm mitochondria appears to be a particularly important part of epididymal maturation.
Acrosome Reaction ; Aging ; Animals ; Epididymis ; growth & development ; physiology ; Humans ; Male ; Mammals ; Mice ; Proteome ; Sperm Capacitation ; physiology ; Spermatozoa ; physiology

OBJECTIVETo assess the relationships among human follicular fluid-induced acrosome reaction, sperm morphology and in vitro fertilization rates.

METHODSThe relationships among human follicular fluid-induced acrosome reaction, sperm morphology and in vitro fertilization rates were investigated by Spearman rank correlation in 79 infertile couples. And the sperm morphology analysis was performed by crystal violet staining and based on strict criteria.

RESULTSA significant positive correlation was found between the percentage of human follicular fluid-induced acrosome reaction and that of normal sperm morphology (n = 49, r = 0.3763, P < 0.01), but no significant correlation was observed either between the percentage of human follicular fluid-induced acrosome reaction and in vitro fertilization rates or between that of normal sperm morphology and in vitro fertilization rates (n = 21, r = 0.2666, P > 0.05 and n = 50, r = 0.0018, P > 0.05, respectively).

CONCLUSIONThere is a significant positive correlation between the percentage of human follicular fluid-induced acrosome reaction and that of normal sperm morphology, but no such correlation either between the percentage of human follicular fluid-induced acrosome reaction and in vitro fertilization rates or between that of normal sperm morphology and in vitro fertilization rates.

Acrosome Reaction ; physiology ; Adult ; Female ; Fertilization in Vitro ; Follicular Fluid ; Humans ; Infertility, Male ; physiopathology ; therapy ; Male ; Retrospective Studies ; Spermatozoa ; physiology

Ca2+ is an important positive ion in the living body. Recently, there have been quite a few reports about the function of Ca2+ in sperm. Calcium is considered as a regulator of sperm motility, a participant in sperm capacitation, and an essential second messenger for acrosome reaction. This paper reviews the relationship of Ca2+ with sperm function.
Acrosome Reaction ; physiology ; Animals ; Calcium ; physiology ; Humans ; Male ; Sea Urchins ; Second Messenger Systems ; physiology ; Sperm Capacitation ; physiology ; Sperm Motility ; physiology ; Spermatozoa ; physiology

OBJECTIVETobacco smoking is recognized as a general health hazard, and evidence indicates that cigarette smoking affects reproductive health in both men and women. The aim of this study was to provide evidence that cigarette smoking affects male fertility via altering the semen and sperm quality.

METHODSWe evaluated the direct effect of seminal plasma (SP) (in the different dilutions with PBS, 1/0; 1/1; 1/2; 1/6; 1/10) from smokers (SM) on spermatozoa from non-smokers (NSM).

RESULTSExposure of spermatozoa from NSM to the SP from SM yielded an impairment in the membrane integrity by elevation in MDA (Malondialdehyde) levels, a decline in the sperm viability, and a decrease in the number of halos (clear regions around sperm heads due to acrosome reaction on the gelatin slides), in a certain time course.

CONCLUSIONExposure of spermatozoa from the SM to the SP from the NSM resulted in the improvement in sperm dysfunction. It may indicate that removal of smokers SP and then subsequent reconstitution with SP containing sufficient antioxidant systems could be of clinical significance in the various assisted reproductive technologies (ARTs) applied for smokers.

Acrosome Reaction ; physiology ; Adult ; Cell Membrane ; physiology ; Humans ; Male ; Semen ; physiology ; Smoking ; adverse effects ; Sperm Count ; Sperm Motility ; physiology ; Spermatozoa ; physiology