A seminal plasma factor and aprotinin are capable of inhibiting the movement of demembranated rea... more A seminal plasma factor and aprotinin are capable of inhibiting the movement of demembranated reactivated rabbit spermatozoa. These inhibitors can be overcome by the addition of ATP. This reversibility could be explained by a common binding receptor for the inhibitors and MgATP. The respective affinities for the receptor are dependent on whether the microtubules are sliding or resting.
Spermatozoa undergo a variety of changes during their life that are prerequisites to their matura... more Spermatozoa undergo a variety of changes during their life that are prerequisites to their maturation and ability to fertilize eggs. Mammalian sperm capacitation and acrosome reaction are regulated by signal transduction systems involving cyclic adenosine monophosphate (cAMP) as a second messenger. This second messenger acts through the activation of protein kinase A (PKA) and indirectly regulates protein tyrosine phosphorylation. cAMP levels are controlled by a balance of phosphodiesterases (PDEs) and adenylyl cyclase (AC) enzymatic activities, which are responsible for its degradation and production, respectively. The aim of this study was to evaluate the possible relationship between the intracellular levels of cAMP and PDE and PKA activities during human sperm capacitation induced by fetal cord serum ultrafiltrate (FCSu) and acrosome reaction induced by calcium ionophore A23187. We report that PKA activity was higher in capacitating than in noncapacitating spermatozoa and that i...
Although recent evidence indicated that the production of reactive oxygen species (ROS) by human ... more Although recent evidence indicated that the production of reactive oxygen species (ROS) by human spermatozoa may be involved in the regulation of capacitation, very little is known about the role of ROS in the acrosome reaction. To address this issue, Percoll-washed spermatozoa were incubated in Ham's F-10 medium in the absence (no capacitation) or presence (capacitation) of fetal cord serum ultrafiltrate (FCSu) or progesterone. The effects of the ROS scavengers, superoxide dismutase (SOD), and catalase were then tested on the acrosome reaction induced by lysophosphatidylcholine (LPC), A23187, and ultrafiltrates from follicular fluid (FFu) and FCSu, as well as on the protein tyrosine phosphorylation associated with this process. 2-Methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo [1,2-a] pyrazin-3-one (MCLA)-amplified chemiluminescence was used to determine the extracellular superoxide (O2.-) production from spermatozoa. The observations that both SOD and catalase reduced (in the ca...
Recent evidence indicated that human sperm capacitation is associated with an increased productio... more Recent evidence indicated that human sperm capacitation is associated with an increased production of superoxide anion (O2.-). To further study the role and importance of O2.- in capacitation, we investigated whether the O2.- generation is a general feature of capacitating spermatozoa, irrespective of the inducer used, and is correlated with capacitation levels and increased tyrosine phosphorylation of two sperm proteins (p105/p81). We also studied the time courses of O2.- production and action. Percoll-washed human spermatozoa were incubated in Ham's F-10 medium, supplemented or not supplemented with various capacitation inducers and in the presence or absence of superoxide dismutase (SOD). Sperm capacitation was measured by induction of the acrosome reaction with lysophosphatidylcholine, O2.- production was measured by chemiluminescence, and tyrosine phosphorylation was measured by immunodetection after electrophoresis and western blotting of sperm proteins. Progesterone and u...
To characterize the very vigorous type of motility observed in the semen of some infertile men an... more To characterize the very vigorous type of motility observed in the semen of some infertile men and to compare the superoxide anion scavenging capacity of the seminal plasma from these men and that from normal men. Patients consulting for infertility related to sperm motility problems and men presenting as sperm donors. Motility patterns and measurements of sperm motility parameters were evaluated by computer-assisted digital image analysis system. The superoxide anion scavenging capacity of seminal plasma was measured by inhibition of nitroblue tetrazolium reduction due to the superoxide anion generated by the combination xanthine plus xanthine oxidase. Spermatozoa from 9 of 68 semen samples with normal sperm concentration, morphology, and percentage of motility showed the typical motility patterns observed during hyperactivation (HA) and a significant level of HA (16% +/- 3%) as compared with those in semen (2.3% +/- 0.3%) from fertile volunteers. The superoxide anion scavenging ca...
Seminal plasma contains a motility inhibitor of demembranated reactivated spermatozoa. We investi... more Seminal plasma contains a motility inhibitor of demembranated reactivated spermatozoa. We investigated its origin within the reproductive tract. The highest level of inhibitor was detected in seminal vesicle fluids from the three species investigated (bull, rat, rabbit). Significant levels of inhibitor were also observed in prostatic fluids. Testes and epididymal fluids, as well as bulbo-urethral and coagulating gland homogenates were essentially devoid of inhibitor. On a mg protein basis, the inhibitor in seminal vesicle fluid was about four times less active than the inhibitor of seminal plasma. The high level of inhibitor in seminal plasma can not be explained by the synergistic effect of the combination of seminal vesicle, prostatic and epididymal fluids. Dialysis experiments suggested that the high level of inhibitor in seminal plasma was mainly due to the presence of a dialysable activator. This activator is capable of potentiating up to four-fold the inhibitor present in semi...
The presence of motility inhibitors in seminal plasma and within spermatozoa from control and inf... more The presence of motility inhibitors in seminal plasma and within spermatozoa from control and infertile men with poor sperm motility was investigated using demembranated reactivated human spermatozoa. No difference was found in the inhibitory capacities in seminal plasma of patients with poor sperm motility (less than 50%) when compared with that of fertile controls with motility above 50%. No correlation was observed between inhibitory capacity and sperm motility. However, when extracts of spermatozoa from these patients were tested for the presence of inhibitor, it was observed that three of nine patients had an inhibitor in their sperm extract. By contrast, all sperm extracts from fertile control subjects were devoid of inhibitor. It was concluded that the presence of a motility inhibitor in seminal plasma does not explain the poor sperm motility observed in patients. The presence of a motility inhibitor within spermatozoa, however, may represent an important factor in the etiolo...
Levels of protein-carboxyl methylase (PCM) activity were measured in spermatozoa from infertile p... more Levels of protein-carboxyl methylase (PCM) activity were measured in spermatozoa from infertile patients with less than 50% sperm motility and compared with those of normal fertile controls. When spermatozoa were washed by a standard centrifugation procedure, the level of PCM activity in a subgroup of patients with sperm motility ranging from 0% and 20% (24.0 +/- 5.2 pmol/mg protein, mean +/- standard error of the mean) was significantly different from that of controls (35.9 +/- 2.3 pmol/mg). However, when the entire population of patients with sperm motility ranging from 0% to 50% (32.6 +/- 6.2 pmol/mg) was compared with controls, no significant difference was observed in sperm PCM levels. With this standard washing procedure no significant relationship (r = 0.28; P greater than 0.05) between sperm PCM activity and motility was observed. By contrast, when spermatozoa were washed on a Percoll gradient, to eliminate other cellular elements, both groups of patients with 0% to 20% (14....
A seminal plasma factor and aprotinin are capable of inhibiting the movement of demembranated rea... more A seminal plasma factor and aprotinin are capable of inhibiting the movement of demembranated reactivated rabbit spermatozoa. These inhibitors can be overcome by the addition of ATP. This reversibility could be explained by a common binding receptor for the inhibitors and MgATP. The respective affinities for the receptor are dependent on whether the microtubules are sliding or resting.
Spermatozoa undergo a variety of changes during their life that are prerequisites to their matura... more Spermatozoa undergo a variety of changes during their life that are prerequisites to their maturation and ability to fertilize eggs. Mammalian sperm capacitation and acrosome reaction are regulated by signal transduction systems involving cyclic adenosine monophosphate (cAMP) as a second messenger. This second messenger acts through the activation of protein kinase A (PKA) and indirectly regulates protein tyrosine phosphorylation. cAMP levels are controlled by a balance of phosphodiesterases (PDEs) and adenylyl cyclase (AC) enzymatic activities, which are responsible for its degradation and production, respectively. The aim of this study was to evaluate the possible relationship between the intracellular levels of cAMP and PDE and PKA activities during human sperm capacitation induced by fetal cord serum ultrafiltrate (FCSu) and acrosome reaction induced by calcium ionophore A23187. We report that PKA activity was higher in capacitating than in noncapacitating spermatozoa and that i...
Although recent evidence indicated that the production of reactive oxygen species (ROS) by human ... more Although recent evidence indicated that the production of reactive oxygen species (ROS) by human spermatozoa may be involved in the regulation of capacitation, very little is known about the role of ROS in the acrosome reaction. To address this issue, Percoll-washed spermatozoa were incubated in Ham's F-10 medium in the absence (no capacitation) or presence (capacitation) of fetal cord serum ultrafiltrate (FCSu) or progesterone. The effects of the ROS scavengers, superoxide dismutase (SOD), and catalase were then tested on the acrosome reaction induced by lysophosphatidylcholine (LPC), A23187, and ultrafiltrates from follicular fluid (FFu) and FCSu, as well as on the protein tyrosine phosphorylation associated with this process. 2-Methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo [1,2-a] pyrazin-3-one (MCLA)-amplified chemiluminescence was used to determine the extracellular superoxide (O2.-) production from spermatozoa. The observations that both SOD and catalase reduced (in the ca...
Recent evidence indicated that human sperm capacitation is associated with an increased productio... more Recent evidence indicated that human sperm capacitation is associated with an increased production of superoxide anion (O2.-). To further study the role and importance of O2.- in capacitation, we investigated whether the O2.- generation is a general feature of capacitating spermatozoa, irrespective of the inducer used, and is correlated with capacitation levels and increased tyrosine phosphorylation of two sperm proteins (p105/p81). We also studied the time courses of O2.- production and action. Percoll-washed human spermatozoa were incubated in Ham's F-10 medium, supplemented or not supplemented with various capacitation inducers and in the presence or absence of superoxide dismutase (SOD). Sperm capacitation was measured by induction of the acrosome reaction with lysophosphatidylcholine, O2.- production was measured by chemiluminescence, and tyrosine phosphorylation was measured by immunodetection after electrophoresis and western blotting of sperm proteins. Progesterone and u...
To characterize the very vigorous type of motility observed in the semen of some infertile men an... more To characterize the very vigorous type of motility observed in the semen of some infertile men and to compare the superoxide anion scavenging capacity of the seminal plasma from these men and that from normal men. Patients consulting for infertility related to sperm motility problems and men presenting as sperm donors. Motility patterns and measurements of sperm motility parameters were evaluated by computer-assisted digital image analysis system. The superoxide anion scavenging capacity of seminal plasma was measured by inhibition of nitroblue tetrazolium reduction due to the superoxide anion generated by the combination xanthine plus xanthine oxidase. Spermatozoa from 9 of 68 semen samples with normal sperm concentration, morphology, and percentage of motility showed the typical motility patterns observed during hyperactivation (HA) and a significant level of HA (16% +/- 3%) as compared with those in semen (2.3% +/- 0.3%) from fertile volunteers. The superoxide anion scavenging ca...
Seminal plasma contains a motility inhibitor of demembranated reactivated spermatozoa. We investi... more Seminal plasma contains a motility inhibitor of demembranated reactivated spermatozoa. We investigated its origin within the reproductive tract. The highest level of inhibitor was detected in seminal vesicle fluids from the three species investigated (bull, rat, rabbit). Significant levels of inhibitor were also observed in prostatic fluids. Testes and epididymal fluids, as well as bulbo-urethral and coagulating gland homogenates were essentially devoid of inhibitor. On a mg protein basis, the inhibitor in seminal vesicle fluid was about four times less active than the inhibitor of seminal plasma. The high level of inhibitor in seminal plasma can not be explained by the synergistic effect of the combination of seminal vesicle, prostatic and epididymal fluids. Dialysis experiments suggested that the high level of inhibitor in seminal plasma was mainly due to the presence of a dialysable activator. This activator is capable of potentiating up to four-fold the inhibitor present in semi...
The presence of motility inhibitors in seminal plasma and within spermatozoa from control and inf... more The presence of motility inhibitors in seminal plasma and within spermatozoa from control and infertile men with poor sperm motility was investigated using demembranated reactivated human spermatozoa. No difference was found in the inhibitory capacities in seminal plasma of patients with poor sperm motility (less than 50%) when compared with that of fertile controls with motility above 50%. No correlation was observed between inhibitory capacity and sperm motility. However, when extracts of spermatozoa from these patients were tested for the presence of inhibitor, it was observed that three of nine patients had an inhibitor in their sperm extract. By contrast, all sperm extracts from fertile control subjects were devoid of inhibitor. It was concluded that the presence of a motility inhibitor in seminal plasma does not explain the poor sperm motility observed in patients. The presence of a motility inhibitor within spermatozoa, however, may represent an important factor in the etiolo...
Levels of protein-carboxyl methylase (PCM) activity were measured in spermatozoa from infertile p... more Levels of protein-carboxyl methylase (PCM) activity were measured in spermatozoa from infertile patients with less than 50% sperm motility and compared with those of normal fertile controls. When spermatozoa were washed by a standard centrifugation procedure, the level of PCM activity in a subgroup of patients with sperm motility ranging from 0% and 20% (24.0 +/- 5.2 pmol/mg protein, mean +/- standard error of the mean) was significantly different from that of controls (35.9 +/- 2.3 pmol/mg). However, when the entire population of patients with sperm motility ranging from 0% to 50% (32.6 +/- 6.2 pmol/mg) was compared with controls, no significant difference was observed in sperm PCM levels. With this standard washing procedure no significant relationship (r = 0.28; P greater than 0.05) between sperm PCM activity and motility was observed. By contrast, when spermatozoa were washed on a Percoll gradient, to eliminate other cellular elements, both groups of patients with 0% to 20% (14....
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