Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “EJACULATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55Linked to original sources
PubMed2003

Expression of aromatase in human ejaculated spermatozoa: a putative marker of motility.

Cytochrome p450 aromatase (p450arom) is a key enzyme responsible for the irreversible transformation of androgens into estrogens. In the present study, we have analysed the ability of human ejaculated spermatozoa to produce estrogens and for that purpose we have looked for the expression of specific aromatase transcript and protein. We have confirmed the presence of p450arom transcript in all normospermic purified samples by nested PCR. The sequence of PCR products from purified spermatozoa shares 98% identity with published human p450arom sequence. Using a semi-quantitative approach, we have observed in immotile sperm a significant decrease (28%) of the aromatase/glyceraldehyde-3-phosphate dehydrogenase ratio compared with the motile sperm fraction. On Western blot with a monoclonal antibody directed against aromatase, we have detected two bands (53 and 49 kDa) in microsome preparations from purified spermatozoa. In total protein extracts of purified spermatozoa (with and without cytoplasmic droplets), we have only found the aromatase as a 49 kDa band with a stronger intensity when cytoplasmic droplets are present. Moreover, the band seems to be weaker in immotile spermatozoa (with and without cytoplasmic droplets). Our data demonstrate the expression of aromatase both in terms of mRNA and protein in each sample of human purified spermatozoa and in addition, our results suggest that aromatase could be concerned with the acquisition of sperm motility.

Adult↗
PubMed1991

Successful pregnancy using known donor oocytes fertilized in vitro by spermatozoa obtained by electro-ejaculation from a quadriplegic husband.

A 34-year-old quadriplegic man with a C6/C7 spinal cord lesion of 10 years' duration fathered a child with his 35-year-old wife who had undergone a premature menopause 10 years earlier. Pregnancy was achieved from in-vitro fertilization of two oocytes donated by the wife's sister using spermatozoa from the husband obtained by repeated electro-ejaculation techniques. A healthy male infant weighing 2250 g was delivered by Caesarean section at 37 weeks following mild pre-eclampsia.

Adult↗
PubMed1992

Regulation of cyclic adenosine monophosphate synthesis in human ejaculated spermatozoa. I. Experimental conditions to quantitate membrane-bound adenylyl cyclase activity.

Although cyclic adenosine monophosphate (cAMP) is an important regulator of motility and metabolism in human spermatozoa, little is known on the cellular system responsible for its synthesis. Here, we investigated the experimental conditions directly to quantitate adenylyl cyclase (AC) activity synthesizing cAMP in human ejaculated spermatozoa and analysed the general properties of the enzyme. A 10,000 g membrane fraction was prepared from washed sperm cells homogenized by sonication. AC activity was monitored by the direct conversion of [alpha-32P]adenosine triphosphate (ATP) into [32P]cAMP. Using a nucleoside triphosphate regenerating system to ensure availability of ATP substrate, the human sperm AC showed a steady production of cAMP for at least 1 h. The assay was optimized for pH, buffer concentration, membrane protein and substrate concentration. Activity was dependent upon the presence of Mn2+ as a divalent cation and showed a pH optimum between 7.0 and 8.5. Optimal activity required 5 mM ATP, 1 mM ethylenediamine tetraacetic acid (EDTA) and 20-40 mM total MnCl2. Dependence on Mn2+ was not mandatory; Mg2+ at 5-40 mM also supported significant activity, but the activity was 4-6 times lower than that with Mn2+. Regardless of the presence of Mn2+ or Mg2+ as divalent cation in the assay, human sperm AC was insensitive to the regulatory ligands NaF, guanine nucleotide or forskolin. Insensitivity to these ligands supports the proposal that this enzyme system does not contain a stimulatory guanine nucleotide-binding regulatory protein and that its catalytic component is unique and different from that of somatic cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1992

Regulation of cyclic adenosine monophosphate synthesis in human ejaculated spermatozoa. II. The role of calcium and bicarbonate ions on the activation of adenylyl cyclase.

In this study, we have applied our previous data describing the experimental conditions necessary for expression of cyclic adenosine monophosphate (cAMP)-synthesizing adenylyl cyclase in human ejaculated spermatozoa, to investigate the direct effects of calcium (Ca2+) and bicarbonate (HCO3-) upon activation of the enzyme in vitro. We report that the effects of Ca2+ and HCO3- were significantly dependent on the status of the enzyme activity. Thus, at a near saturating (10 mM) concentration of MnCl2 giving high enzyme activity, addition of less than 10 mM HCO3- did not affect adenylyl cyclase activity and higher concentrations inhibited the enzyme, with 50 mM HCO3- reducing the activity by 33%. Also, addition of less than 20 mM CaCl2 alone or in combination with 10 mM HCO3- did not significantly change the enzyme activity. In great contrast, enzyme activation was highly responsive to Ca2+ and HCO3- when MnCl2 was present at a concentration giving submaximal enzyme activity. Thus, at 2 mM MnCl2, adenylyl cyclase was markedly increased by CaCl2 concentrations between 10 and 100 mM. The activation was further enhanced by increasing concentrations of HCO3-, with 50 mM HCO3- giving the highest activity at 50-100 mM CaCl2. Activation by CaCl2 was also observed in the absence of added MnCl2, being significantly greater than basal activity at 10 mM CaCl2 and maximal at 100 mM CaCl2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1992

Purification and characterization of two casein kinases from ejaculated bovine spermatozoa.

Two protein kinases active on casein and phosvitin were partially purified from the soluble fraction of ejaculated bovine spermatozoa. They were operationally termed casein kinase A and B based on the order of their elution from a phosphocellulose column. CK-A showed an approximate molecular mass of 38 kDa, and it phosphorylated serine residues of casein and phosvitin utilizing ATP as a phosphate donor (Km 19 microM). Enzyme activity was maximal in the presence of 10 mM MgCl2, whereas it decreased in the presence of spermine, polylysine, quercetin, and NaCl (20-250 mM). CK-B seemed to have a monomeric structure of about 41 kDa; it underwent autophosphorylation and cross-reacted with polyclonal antibodies raised against recombinant alpha, but not beta, subunit of human type 2 casein kinase. It phosphorylated both serine and threonine residues of casein and phosvitin, utilizing ATP (Km 12 microM) but not GTP as a phosphate donor. Threonine was more affected in the phosphorylated phosvitin than in the partially dephosphorylated substrate. CK-B was active toward the synthetic peptide Ser-(Glu)5 and calmodulin (in the latter case, in the presence of polylysine), and it was activated by spermine, polylysine, MgCl2 (30 mM), and NaCl (20-400 mM). The activity of the enzymes was not affected by cAMP, or the heat-stable inhibitor of the cAMP-dependent protein kinase, or calcium.

Animals↗
PubMed2006

Visualization of GM1 with cholera toxin B in live epididymal versus ejaculated bull, mouse, and human spermatozoa.

The organization of membrane subdomains in mammalian sperm has recently generated controversy, with several reports describing widely differing localization patterns for the ganglioside GM1. Using the pentameric B subunit of cholera toxin (CTB), we found GM1 to be restricted to the plasma membrane overlying the acrosome in the heads of live murine sperm. Interestingly, CTB had minimal binding to live bovine and human sperm. To investigate whether this difference in GM1 localization was because of species differences or differences between collection from the epididymis (mouse) or an ejaculate (bull, human), we examined epididymal bovine and human sperm. We found that GM1 localized to the plasma membrane overlying the acrosome in sperm from these species. To determine whether some component of seminal plasma was interfering with the ability of CTB to access GM1, we incubated epididymal mouse sperm with fluid from murine seminal vesicles and epididymal bull sperm with bovine seminal plasma. This treatment largely abolished the ability of the CTB to bind to GM1, producing a fluorescence pattern similar to that reported for the human. The most abundant seminal plasma protein, PDC-109, was not responsible for this loss. As demonstration that the seminal plasma was not removing GM1, sperm exposed to seminal plasma were fixed before CTB addition, and again displayed fluorescence over the acrosome. These observations reconcile inconsistencies reported for the localization of GM1 in sperm of different species, and provide evidence for the segregation of GM1 to a stable subdomain in the plasma membrane overlying the acrosome.

Animals↗
PubMed1986

Acrosomal status in fresh and capacitated human ejaculated sperm.

The acrosomal status of human sperm was evaluated by immunofluorescence utilizing a specific monoclonal antibody that recognizes target antigen(s) localized in the acrosomal cap region. Spontaneous acrosomal loss was first examined in sperm preparations used for successful in vitro fertilization of human eggs. In these sperm populations, less than 20% of the sperm underwent degenerative or spontaneous acrosomal loss following 24 h of incubation. The correlation of acrosomal loss with changes in motility and viability suggested that sperm senescence was not necessarily coupled to acrosomal loss. Chemical induction of acrosomal loss by calcium ionophore A23187 and lysophosphatidylcholine (LPC) was characterized. Maximal ionophore induction (10 microM A23187 in media containing calcium) was observed in cells exposed to capacitating conditions in vitro; sperm exposed to noncapacitating conditions did not readily acquire the ability to respond to ionophore. The reaction induced by ionophore was slow (60 min), and at least 30% of the cells were always resistant to induction. In contrast, LPC induced rapid, synchronous acrosomal loss in either freshly ejaculated or capacitated sperm in the presence or absence of extracellular calcium, suggesting that this loss was not a physiologic reaction. These studies may provide a basis for evaluating capacitation and ultimately fertility potential in the human male.

Acrosome↗
PubMed1987

Similarity in ejaculate-endocrine characteristics in captive versus free-ranging cheetahs of two subspecies.

Ejaculate-endocrine characteristics were measured in 23 captive cheetahs (Acinonyx jubatus jubatus) in North American zoos and in 8 free-ranging cheetahs (A.j. raineyi) in eastern Africa (Tanzania). A standardized electroejaculation protocol was used, and numbers of motile spermatozoa were similar (p greater than 0.05) between groups. Of the spermatozoa collected by electroejaculation, 70.6 +/- 3.3% and 75.9 +/- 4.4% were morphologically abnormal in the captive "North American" and in the free-ranging, eastern African populations, respectively. Adrenal activity, as measured by an acute, temporal rise and fall in serum cortisol levels during and after electroejaculation, was no different (p greater than 0.05) between groups. Although serum luteinizing hormone (LH) levels were less (p less than 0.05) in the free-ranging than in the captive animals, serum testosterone concentrations were similar. The data indicate that the comparatively poor reproductive performance of cheetahs maintained in zoological parks is not attributable to a captivity-induced response afflicting the male. Furthermore, there is no evidence that ejaculate/endocrine characteristics differ between the two subspecies. Because adrenal/gonadal activity and the number of pleiomorphic spermatozoa are similar between the test groups, the results suggest that spermatozoal diversity originates as a result of the extreme genetic monomorphism observed universally in the species.

Acinonyx↗
PubMed1989

Effect of L-carnitine and L-aminocarnitine on calcium transport, motility, and enzyme release from ejaculated bovine spermatozoa.

Experiments were performed to further elucidate the role of gamma-amino-beta-hydroxybutyric acid trimethylbetaine (carnitine) on the metabolism and functions of spermatozoa. Addition of 20 mM L-carnitine to suspensions of ejaculated bovine spermatozoa resulted in an increase of cellular calcium transport, whereas 20 mM L-aminocarnitine (an inhibitor of carnitine palmitoyltransferase) caused an inhibition of this process. Both L-carnitine and L-aminocarnitine inhibited the progressive motility of spermatozoa, and the oxygen consumption as well as the release of the enzymes hyaluronidase and glutamate-oxaloacetate transaminase from spermatozoa. Labeled carnitine was rapidly taken up by spermatozoa by a process strongly dependent on temperature and extracellular concentration of carnitine. It is concluded that the effects produced by high concentrations of carnitine or aminocarnitine are mainly due to interactions of these compounds with the cellular membranes of spermatozoa.

Acyltransferases↗
PubMed1991

Determination of the capacity of ram epididymal and ejaculated sperm to undergo the acrosome reaction and penetrate ova.

An understanding of epididymal maturation of sperm requires descriptions of changes in membrane properties and their relation to changes in cell function. While sperm membranes have been studied in some detail in rams, few reports address associated functional changes. This report provides such data by evaluating (a) the time course of sperm acrosome reaction (AR) induction for cells from each epididymal region; (b) the capacity of epididymal sperm to penetrate ova; (c) differences in physiological AR and general sperm degeneration; and (d) acrosin release of epididymal sperm. Ram epididymal (caput, corpus, and proximal and distal cauda) and ejaculated (EJ) sperm were incubated in vitro to assess their capacity to undergo an AR. Light microscopy revealed that in sperm populations which had traversed the proximal cauda epididymidis, greater than or equal to 50% exhibited an endogenous AR in less time (less than 17 h) than did sperm isolated from more proximal regions of the epididymis (22-greater than 50 h). Heparin added to sperm did not stimulate the AR in epididymal or EJ sperm, whereas addition of a calcium ionophore (A23187) increased AR rates for cauda and EJ sperm, but not caput or corpus sperm. A second experiment evaluating percent AR, percent motile cells, and percent hamster ova penetrated revealed that sperm isolated from regions proximal to the cauda epididymidis failed to penetrate ova. When cauda or EJ sperm exhibited motility greater than 5% and AR greater than 24%, penetration of hamster eggs occurred. Comparisons of acrosomal integrity by electron or light microscopy were not different for sperm at any stage of epididymal maturation, suggesting that minimal nonspecific membrane changes occur and that light microscopy is valid for evaluating the acrosomal status of ram spermatozoa. Acrosin activity (sperm bound and dissociated) also was measured. Both total activity and release of acrosin from sperm to the medium during an 8-h incubation was greater for mature than for immature sperm. Results from these experiments are discussed in relation to the changes that must occur in sperm as they acquire the capacity to undergo an AR and penetrate hamster ova.

Acrosin↗
PubMed1994

Penetration of porcine oocytes during maturation in vitro by cryopreserved, ejaculated spermatozoa.

The present study was conducted to examine the penetrability in vitro of immature porcine oocytes with or without cumulus cells. Porcine oocytes were cultured for 0-36 h, at 39 degrees C in 5% CO2 in air, in modified tissue culture medium 199 (TCM-199B at pH 7.4) supplemented with 10 IU eCG/ml, 10 IU hCG/ml, and 1 microgram estradiol-17 beta/ml. At various times after the beginning of culture, some oocytes were freed from the cumulus (cumulus and corona cells), and cumulus-intact or cumulus-free oocytes were inseminated with cryopreserved ejaculated spermatozoa in TCM-199B (pH 7.8) containing 5 mM caffeine. When cumulus-free oocytes were examined 14 h after insemination, high proportions (69-84%) were penetrated and there were no significant differences among different periods of maturation culture. The incidence (47-68%) of polyspermy and the number (1.7-3.1) of spermatozoa that penetrated per oocyte were also not significantly different among oocytes cultured for 0-36 h. In cumulus-intact oocytes, however, the first evidence of penetration (15%) was observed in oocytes cultured for 6 h. The penetration rates increased significantly as the period of culture was prolonged up to 24 h. Almost all (95-100%) oocytes were penetrated when they were inseminated 24-36 h after the beginning of culture, by which time the cumulus masses showed moderate to complete expansion except for the corona radiata. A similar correlation was also observed for incidence of polyspermy and number of spermatozoa penetrated per oocyte. The presence of well-expanded cumulus around the oocyte during fertilization promoted male pronuclear formation in penetrant oocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Management of ejaculation pain with topiramate: a case report.

A 39-year-old male presented with penile pain related to ejaculation. No urogenital, infectious, or neurologic diseases were associated with the symptoms. The pain was refractory to conventional analgesics and several neuropathic pain therapies. Oral topiramate was titrated to 75 mg daily, and within a month, the patient's pain improved from 8 to 1 out of 10, which has been maintained for 6 months.

Adult↗
PubMed2004

Risperidone-induced retrograde ejaculation: case report and review of the literature.

Medication adherence with antipsychotics is adversely impacted by the burden of untoward adverse effects. In particular, sexual side-effects may interfere with compliance, but are often underreported by patients. Sexual dysfunction related to hyperprolactinemia is commonly described, but ejaculatory disturbance due to potent alpha1 adrenergic antagonism may also occur, and has been reported frequently with certain typical antipsychotics such as thioridazine, but rarely with atypical antipsychotics. Presented here is the case of a 51 year old male with schizophrenia who developed retrograde ejaculation on high dose risperidone therapy (8 mg/day) with prompt resolution of symptoms upon dose reduction. The absence of decreased libido or erectile dysfunction indicates that alpha1 adrenergic antagonism and not low serum testosterone due to hyperprolactinemia is the etiology for this side-effect. This case illustrates another mechanism for sexual adverse effects, and the need for routine inquiry into sexual dysfunction during atypical antipsychotic therapy.

Antipsychotic Agents↗
PubMed2004

Fecundity and MHC affects ejaculation tactics and paternity bias in sand lizards.

We demonstrate that extending copulation enhances probability of paternity in sand lizards and that determinants of copulation duration depend on a males' mating order (first or second). First males, with no information on presence of rivals, extend copulation when mating with a more fecund female. Second males, however, adjust copula duration in relation to a first male's relatedness with his female, which there is reason to believe can be deduced from the MHC-related odor of the copulatory plug. Male-female relatedness negatively influences a male's probability of paternity, and when second males are in a favored role (i.e., the first male is the one more closely related to the female), second males transfer larger ejaculates, resulting in higher probability of paternity. This result corroborates predictions from recent theoretical models on sperm expenditure theory incorporating cryptic female choice and sexual conflict. More specifically, the results conform to a "random roles" model, which depicts males as being favored by some females and disfavored by others, but not to a "constant-type" model, in which a male is either favored or disfavored uniformly by all females in a population.

Animals↗
PubMed2003

Premature ejaculation in non-insulin-dependent diabetic patients.

Aim of the study was to assess the prevalence and to analyse risk factors for premature ejaculation (PE) in patients with non-insulin-dependent diabetes. A total of 676 male diabetic patients were enrolled in this study. Patients were screened for PE. At the screening time, patients were also interviewed for sociodemographic data that included age, education, occupation and marital status. Medical history included diabetes, duration of diabetes and diabetes-related complications. Clinical and laboratory assessment included body mass index and glycosylated haemoglobin. Mean age for the study sample was 53.4 +/- 10.4 years. The prevalence of PE was 32.4% in patients below 50 years, which increased to 67.6% in patients above 50 years. Of patients without PE, 31.4% were below 50 years compared with 68.6% above 50 years of age (p > 0.05). Patients with >10 years of diabetes were 2.7 times as likely to report PE as men with diabetes of <5 years (p < 0.05). Men with poor metabolic control were 9.6 times as likely to report PE as those with good metabolic control (p < 0.05). Patients without PE were four times as likely to have normal erectile function as those with PE (p < 0.05). There was a significant association between PE and cardiovascular diseases (p < 0.05). PE is common among diabetic patients. The study offers a quantitative estimate of the prevalence of PE and its main risk factors in diabetic patients.

Adult↗
PubMed2005

Premature ejaculation: presentation and associations. An audit of patients attending a sexual problems clinic.

The diagnostic register and case summaries of all male and female patients who attended the clinic on account of one or more sexual symptoms or relationship problems between 1 January 1992 and 31 December 1997 were reviewed. The index symptom or problem was considered the complaint that caused the patient most concern. When patients or couples were experiencing more than one sexual problem, the concomitant problems were tabulated against the index symptom. During this period, 1,056 (440 men and 616 women) patients with sexual symptoms were seen and 131 couples attended primarily with relationship problems. Overall, 18.2% of men referred to the clinic with sexual problems had premature ejaculation (PE), but this was the index symptom in only 11.6% of men. There was a high occurrence of PE in the partners of women presenting with sexual symptoms. Among couples presenting with relationship dissatisfaction or conflict, 18.3% of the male partners had ongoing PE.

Ejaculation↗
PubMedDate not supplied

A double-blind trial of clomipramine in premature ejaculation.

A double-blind clinical trial was designed to study the effect of clomipramine in 50 patients complaining of rapid ejaculation. Patients were divided into two groups and each group received 2 periods of 6 consecutive weeks' treatment with drug and placebo, so that comparison can be made between drug and placebo within each group and between the two groups. Analysis of collected data showed a significantly higher percentage of satisfactory performances with the drug than with placebo and maintenance of the beneficial effect after the drug was replaced by placebo.

Adult↗
PubMedDate not supplied

Ion-exchange chromatography of amino acids in ejaculates of diabetics.

30 amino acids and their derivatives could be found in the ejaculates of humans by ion-exchange chromatography. There were significant differences between diabetics and controls in the levels of threonine, serine, glutamine, glycine, iso-leucine, leucine, tyrosine, phenylalanine, histidine and in 3-methyl-histidine. There was a positive correlation between levels of certain amino acids and the number of pathologically motile spermatozoa, particularly microforms and head alterations. An impaired Krebs cycle function may explain an elevation of amino acid levels as they are utilized mainly by this cycle, which function depends on intact substrate flow from glucose catabolism.

Amino Acids↗