Document Detail

The role of calcium in maintaining motility in mouse spermatozoa.
MedLine Citation:
PMID:  7338726     Owner:  NLM     Status:  MEDLINE    
Maintenance of mouse sperm motility requires exogenous Ca+2 in most, but not all, samples of epididymal spermatozoa. In these samples, the loss of motility with time is the same in Tris/NaCl buffer containing 1.7 mM Ca+2 (medium TNC) as it is in complete culture medium used for in vitro fertilization (medium CM) over the first 2 hours; spermatozoa in medium TNC lose motility at more rapid rate thereafter. The cation specificity for maintenance of motility is unusual in that both Sr+2 and Mg+2 substitute for Ca+2, with Mg+2 being the more effective. In the absence of Ca+2, these samples of mouse epididymal spermatozoa in Tris/NaCl buffer (medium TN) lose motility in about 30 minutes. If Ca+2 is added after incubation in TN for 15 minutes, motility is maintained as well as it is in medium TNC. If Ca+2 is added at 30 minutes, motility is partially restored. But if Ca+2 is added after 60 minutes, there is no restoration of motility. Spermatozoa suspended in medium TNC lose motility rapidly on addition of EGTA in excess of the Ca+2 present. Attempts to show uptake of Ca+2 by spectrophotometric assay, by effects of Ca+2 on oxidative metabolism, and by electron probe X-ray microanalysis were unsuccessful; motility is not maintained by entry of Ca+2 into the cells. Our results are consistent with a Ca+2 site on the plasma membrane and suggest that these sites function as oligomers of ordered subunits whose structure requires Ca+2. In the absence of Ca+2, the ability to form the oligomer is lost with time, possibly due to an irreversible conformational change.
L J Heffner; B T Storey
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Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of experimental zoology     Volume:  218     ISSN:  0022-104X     ISO Abbreviation:  J. Exp. Zool.     Publication Date:  1981 Dec 
Date Detail:
Created Date:  1982-06-14     Completed Date:  1982-06-14     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0375365     Medline TA:  J Exp Zool     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  427-34     Citation Subset:  IM    
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MeSH Terms
Calcium / metabolism,  pharmacology*
Cell Membrane / metabolism
Culture Media
Magnesium / pharmacology
Oxygen Consumption
Sperm Motility / drug effects*
Spermatozoa / drug effects*,  metabolism,  physiology
Strontium / pharmacology
Time Factors
Grant Support
Reg. No./Substance:
0/Culture Media; 7439-95-4/Magnesium; 7440-24-6/Strontium; 7440-70-2/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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