Changes in sperm nuclei during spermiogenesis and epididymal maturation

Abstract Mouse and rat spermatid nuclei pass abruptly through developmental stages characterized by increased resistance to disruption by various agents. The mouse spermatid nucleus becomes resistant to sonication at step 12, resistant to digestion by trypsin-DNase at step 15 and resistant to lysis by SDS between the testis and the caput epididymis. These alterations are correlated with changes in the basic nuclear proteins.