- Publication date : 1989-05-19
Leclerc P, Langlais J, Lambert RD, Sirard MA, Chafouleas JG. Effect of heparin on the expression of calmodulin-binding proteins in bull spermatozoa. J. Reprod. Fertil. 1989;85:615-22. PubMed PMID: 2703998.
animals benzamidines calcium calmodulin-binding proteins cattle heparin male sperm capacitation spermatozoa
A 125I-labelled calmodulin gel overlay procedure in the presence and the absence of Ca2+ was used to evaluate bull spermatozoa calmodulin-binding proteins. Frozen spermatozoa were thawed, washed and incubated for 6 h before being processed for SDS polyacrylamide gel electrophoresis and the 125I-labelled calmodulin gel overlay procedure. In non-incubated spermatozoa, up to 14 binding proteins were detected. Some exhibited greater calmodulin binding in the presence of Ca2+ while others exhibited greater binding when Ca2+ was absent. When heparin (2 micrograms/ml) was present in the incubation medium, a decrease in the calmodulin binding to the proteins of Mr 28,000 and 30,000 was detected in the presence of Ca2+ and EGTA. This effect of heparin was time- and dose-dependent and was increased by the presence of the acrosin inhibitor benzamidine. Sperm capacitation could thus be related to a decrease in the binding of calmodulin to these proteins.