Biology of Reproduction, Vol 21, 173-179, Copyright © 1979 by Society for the Study of Reproduction

Movements of Sodium and Potassium into Epididymal Boar Spermatozoa

¹ Department of Animal Science, University of Minnesota, Saint Paul, Minnesota 55108
² Department of Radiology, University of Minnesota, School of Medicine, Minneapolis, Minnesota 55455
³ Department of Applied Statistics University of Minnesota, Saint Paul, Minnesota 55108

The kinetics of sodium and potassium transport through the membrane of epididymal boar spermatozoa was investigated with radioisotopes in vitro. The rate of exchange for both sodium and potassium, expressed as relative specific activity, was much more rapid in undiluted spermatozoa from lower caput epididymis than in undiluted spermatozoa from the cauda. When caput spermatozoa were diluted in plasma from the cauda, the rate of exchange became similar to that of cauda spermatozoa in cauda plasma but the reciprocal treatment produced no change. Likewise, the rate of exchange for potassium was increased in cauda spermatozoa by diluting them with seminal plasma. Dilution of both caput and cauda contents with biological salt solutions similar in composition to respective plasma, decreased the rate of exchange in both cases for both ions. The findings are discussed relative to sperm coating macromolecules.

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ACKNOWLEDGMENTS The research reported in this publication was supported by grants #HD ROl 06695 from the NICHHD (Crabo and Moore) and #l-RO1-GM25587 from the National Institute of General Medical Sciences (Weisberg). This is scientific publication series #9976 of the Minnesota Agricultural Experiment station.