Enkephalin‐Degrading Enzymes in Normal and Subfertile Human Semen

Irazusta, Jon; Valdivia, Asier; C., David J. Fernández; Agirregoitia, Ekaitz; Ochoa, Carmen; Casis, Luı́s

doi:10.1002/j.1939-4640.2004.tb02848.x

Cited by 40 publications

(32 citation statements)

References 27 publications

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“…APN activity has previously been reported in seminal plasma of different species of mammals (Agrawal and VanhaPerttula, 1986;Huang et al, 1997;Osada et al, 2001;Fernández et al, 2002;Irazusta et al, 2004;Viudes-deCastro et al, 2014). Recently, Viudes de Castro et al (2014) showed that the bioavailability of buserelin acetate when added to the seminal dose appears to be determined by the activity of the existing seminal plasma aminopeptidases.…”

Section: Seminal Plasma Enzyme Activitymentioning

confidence: 74%

“…Furthermore, mammalian seminal plasma aminopeptidases like alanyl aminopeptidase (APN) are involved in many physiological processes. Alterations in APN activity may contribute to the subfertility of human semen in terms of sperm motility, viability, and spermatogenesis, due to its positive correlation with sperm motility and the percentage of dead sperm and its negative correlation with the total number of spermatozoa per millilitre (Irazusta et al, 2004). Additionally, APN is involved in many peptide metabolism pathways by catalysing the degradation of peptides related to these pathways (Cheng et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Determination of enzyme activity in rabbit seminal plasma and its relationship with quality semen parameters

et al. 2015

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The objective of this study was to determine rabbit seminal plasma enzyme activity. Furthermore, correlations between semen parameters and enzyme activity and male age were examined. The study was performed using 17 New Zealand White males from 5 to 9 mo old. Overall, 252 semen samples were collected from bucks from May to September. Semen characteristics were analysed and the seminal plasma was obtained by centrifugation. The activities of alanyl aminopeptidase (APN), aspartate transaminase (AST), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALKP) in the seminal plasma fluid were measured. Significant differences between males were found in APN, GGT, LDH, ALKP and ALT activities (P<0.05). No significant differences between enzyme activity and male age were found. We also observed significant positive correlations between male age and sperm concentration (r=0.26), progressive motility (r=0.17) and amplitude of lateral head displacement (r=0.21), and negative ones between male age and average path velocity (r=-0.56), velocity of the sperm head along its actual curvilinear path (r=-0.61), straight line velocity (r=-0.50), linearity index (r=-0.13), and cytoplasmic droplet (r=-0.33). Furthermore, a significant negative correlation between APN activity and the status of the acrosome (r=-0.20) and significant positive correlations between APN activity and the sperm abnormalities (r=0.21), GGT activity and sperm concentration (r=0.34) and the status of the acrosome (r=0.31), and ALKP activity and sperm concentration were observed (r=0.41). In our study, APN and GGT seem to be the most predictive enzymes for rabbit semen quality.

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Section: Seminal Plasma Enzyme Activitymentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Determination of enzyme activity in rabbit seminal plasma and its relationship with quality semen parameters

et al. 2015

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“…The mechanism involved in increased sperm necrosis with advancing age is unknown but may involve seminal plasma enzymes that regulate sperm death such as aminopeptidase N [18] , pyroglutamyl peptidase I, and prolyl endopeptidase [19] . For obvious reasons, an increase in sperm necrosis would be accompanied by a decline in sperm motility [1,20] .…”

Section: Discussionmentioning

confidence: 99%

Male Age and Sperm Necrosis in Assisted Reproductive Technologies

et al. 2007

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Introduction: Sperm apoptosis is well characterized but studies on the effect of male age and necrozoospermia are lacking. The objectives were: (a) to analyze percentages of apoptotic and necrotic sperm in ejaculates, and (b) to compare the results between younger and older age groups. Materials and Methods: Routine semen analyses were carried out (n = 189 males) and sperm cells were analyzed by dual fluorescence assay Hoechst 33342 and propidium iodide, and the acridine orange test. Results: The percentage of necrotic sperm in the ejaculate increased by 22% for males aged over 35. There was a positive correlation between age and necrosis (R = 0.30). Sperm apoptosis increased by 17% in males aged 45 and older. The population of DNA intact sperm declined in males aged 40 and over (R = –0.21). There were no age-related changes in strict normal morphology, sperm concentration and semen volume. A decrease in rapid progressive motility was correlated (R = –0.24) with male age and was significant after age 35. Conclusions: The study demonstrated increased necrosis, DNA damage and apoptosis while rapid progression and total motility declined with advancing age in the male beginning as early as age 35. The order of the observed changes was sequential, suggesting the involvement of different pathways in sperm necrosis after age 40.

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“…These enzymes are present in both sperm and seminal fractions (69), and their activity in semen is particularly high with respect to other body tissues (70). Interestingly, APN activity levels were found to be altered in semen from subfertile patients, suggesting that this enzyme may play an important role in male fertility (71).…”

Section: Regulation Of Sperm Fertility By the Opioid Systemmentioning

confidence: 99%