Extraction of human and rabbit acrosomes: a comparison of sequential and sonication methods

Two methods for the extraction of acrosomal membranes and enzymes from both human and rabbit spermatozoa were compared. Treatment of spermatozoa with hypotonic MgCl2 (0.05 M) solution causes removal of the plasma membrane, vesiculation, disruption and removal of the outer acrosomal membrane posterior to the equatorial segment with accompanying loss of soluble acrosomal material. Subsequent exposure to Hyamine 2389 and Triton X-100 removes acrosomal material bound to the inner acrosomal membrane with concomitant solubilization of this membrane. The MgCl2 extract from rabbit spermatozoa contained a higher yield of hyaluronidase, acrosin, and total proteinase activities, whereas the subsequent detergent extracts contained higher yields of both arylsulfatase A and B activities. By comparison, after 4 minutes of sonication to separate heads and tails, both rabbit and human spermatozoa when viewed by transmission electron microscopy showed alterations of plasma and outer acrosomal membranes with considerable loss of the acrosomal contents. Analysis of acrosomal enzymes indicates the greatest percentage of all the enzymes assayed was located in the extract obtained by sonication in contrast to either the separated head or tail fractions used for further subcellular extraction. Subsequent treatment with Hyamine and Triton yields only minimal amounts of enzyme activity.