ISSN:
1040-452X
Keywords:
Sperm creatine kinase
;
Sperm CK activity
;
Cellular maturity
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
We have demonstrated earlier that the per sperm creatine-N-phosphotransferase (CK) activity was increased in oligospermic vs. normospermic men. The increased sperm CK activity is related to higher concentrations of cellular CK, which may indicate a defect of cytoplasmic extrusion during spermatogenesis. In the present work, we examined whether in spermatozoa, similar to muscle, there is a change in the synthesis of B-CK and M-CK isoforms during cellular differentation. In 109 normospermic and 50 oligospermic specimens (sperm concentrations 60.6 ± 3.7 vs. 8.8 ± 1.3 million sperm/ml; all values expressed as mean ± SEM), the relative concentrations of the M-CK isoform (M-CK / M-CK+B-CK) were 27.2% ± 2.1% vs. 6.7% ± 0.9% (P 〈 0.001). The per sperm CK activities showed comparable differences (0.21 ± 0.02 vs. 0.89 ± 0.1 CK IU/100 million sperm; P 〈 0.001) in the two groups, and there was a close correlation between per sperm CK activities and M-CK concentrations (R = 0.69, P 〈 0.001, N = 159). This indicates that the loss of cytoplasm and the commencement of M-CK isoform synthesis are related events during the last phase of spermatogenesis, also that the incidence of spermatozoa with incomplete cellular maturation is higher in oligospermic specimens. In characterizing the M-CK, we found that sperm (unlike muscle tissue) lack the MB hybrid of CK dimers. However, in the presence of muscle M-CK, the muscle-sperm MB-CK hybrid has formed. Thus in sperm and muscle the M-CK isoforms are structurally different, whereas the B-CKs are apparently homologous. We suggest that the relative concentrations of sperm M-CK isoform is a biochemical marker of cellular differentiation that may also predict the functional intetrity, such as fertilization potential, of spermatozoa.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrd.1080250307
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