Search PubMedSearch

PubMed · 8671265

Ageing and sperm function.

Abstract

To evaluate the fertilizing capacity of spermatozoa from elderly men, ejaculates from 29 older fathers (mean age 50.3 years) were compared with those from 35 younger fathers (mean age 32.2 years). In addition to conventional semen parameters, sperm functions were studied that have been reported to be positively correlated with the fertilization rate: progressive motility, acrosin activity, inducible acrosome reaction, and chromosome condensation. Sperm concentration and follicle stimulating hormone concentration differed significantly in both groups. With regard to sperm functions there were no differences between older men and younger men, except for decreased sperm motility in the older group which, however, reached nearly normal values according to World Health Organization criteria. Decreased fertility of older couples is obviously more dependent on the age of the female partner. The significance of genetic risks remains to be clarified, especially when methods of assisted reproduction are applied.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G Haidl, A Jung, W B Schill. 1996. Ageing and sperm function.. https://doi.org/10.1093/humrep%2F11.3.558

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Yeast one-hybrid assay identifies YY1 as a binding factor for a proacrosin promoter element.

The proacrosin gene is specifically expressed in the testis and encodes an acrosomal enzyme. Previously, footprint analyses have shown binding of nuclear extracts from testis and brain to a highly conserved 17 bp motif (F1 element: 5'-AACTTCAAAATGGCTCC/T-3') located in the proacrosin promoter. By using this DNA-element as a target in a yeast one-hybrid assay, a cDNA fragment coding for the C-terminal part of the transcription factor YY1 was isolated. The binding of YY1 to this F1 element was confirmed by immunocompetition in EMSA. Because putative YY1 binding sites were also found in the promoters of other testis-specific genes, the YY1 transcription factor could play an important role in testicular gene expression.

Acrosin

PH-20 but not acrosin is involved in sperm penetration of the macaque zona pellucida.

In this study, we investigated the functions of PH-20 and acrosin during the interaction of macaque sperm with the zona pellucida. Both of these sperm enzymes have been reported to be present on the inner acrosomal membrane of acrosome reacted sperm, and have been suggested to play a role during secondary sperm-zona binding in other species. Anti-macaque PH-20 IgG, anti-pig acrosin IgG and soybean trypsin inhibitor (SBTI) were used as probes for immunolocalization of the two proteins at the ultrastructural level, and as reagents for blocking sperm penetration of the macaque zona pellucida in vitro. As a control, we performed similar studies with antibodies to CD-46, which is also located on the inner acrosomal membrane, but has no known function in sperm-zona pellucida interaction. After labeling with anti-acrosin IgG, gold label was not present on the sperm surface before the acrosome reaction, but was detected over the entire head of sperm that were induced to acrosome react with calcium ionophore A23187. In contrast, when sperm were induced to acrosome react by binding to intact zona pellucida, acrosin was present in the acrosomal shroud but not on the inner acrosomal membrane. Similar results were obtained when SBTI was used as a probe for enzyme localization. PH-20 and CD-46 were demonstrated on the inner acrosomal membrane of sperm induced to acrosome react by ionophore treatment and by zona binding. Neither anti-acrosin IgG nor anti-CD-46 IgG affected sperm penetration of the zona at concentrations up to 300 microg/ml, but zona penetration was blocked completely when anti-PH-20 IgG (100 microg/ml) was present during sperm-oocyte interaction. Ultrastructural observations of oocytes incubated with anti-PH-20 IgG showed that acrosomal shrouds were present on the zona surface but no sperm had begun to penetrate into the zona substance. We conclude that anti-PH-20 IgG prevented sperm penetration of the macaque zona pellucida by interference with secondary sperm-zona binding, rather than primary sperm-zona binding or the zona-induced acrosome reaction. Acrosin was not detected on the inner acrosomal membrane of sperm that are induced to acrosome react after zona binding, and acrosin does not appear to be critical for sperm penetration of the macaque zona pellucida.

Acrosin

Purification and partial peptide sequence analysis of the boar proacrosin binding protein.

Boar proacrosin binding protein has been purified and the partial peptide sequence of the CNBr-digested proacrosin binding protein has been determined. Proacrosin binding protein was purified as a proacrosin and proacrosin binding protein complex from the acid extracts of boar spermatozoa through gel filtration. After the proacrosin binding protein was dissociated from proacrosin by freeze-thaw method, the proacrosin binding protein was purified through gel filtration. Fractions containing the proacrosin binding protein were pooled and were concentrated by lyophilization and then subjected to CNBr digestion. Four major CNBr-digested peptides were subjected to N-terminal peptide sequencing. All four showed the same N-terminus sequence.

Acrosin