Isolation and characterization of boar spermatozoa with and without a cytoplasmic droplet

1. Boar semen was separated on a Percoll density gradient into three populations; a low-density band of immature sperm cells containing a cytoplasmic droplet and a high-density doublet band formed by spermatozoa without a cytoplasmic droplet. 2. In these three cell populations four acid hydrolases were determined, viz. (1) alpha-glucosidase; (2) alpha-mannosidase; (3) beta-galactosidase; (4) beta-hexosaminidase. 3. The release of the hydrolases (1), (2) and (3) from cytoplasmic droplet containing spermatozoa was stimulated whereas the release of beta-hexosaminidase was inhibited by calcium ions. 4. The results suggest that acid alpha-glucosidase, alpha-mannosidase and beta-galactosidase are situated in the acrosome whereas acid beta-hexosaminidase is localized predominantly in the cytoplasmic droplet of boar spermatozoa. 5. We conclude that beta-hexosaminidase should prove useful as a biochemical marker for cytoplasmic droplet containing spermatozoa and hence for the number of immature sperm cells in boar semen.