The ability of dehydrated hamster and human sperm nuclei to develop into pronuclei.

To determine whether the nuclei of mature mammalian spermatozoa are resistant to dehydrated conditions, nuclei of hamster and human spermatozoa were freeze-dried or treated with various dehydrating agents before injection into hamster oocytes. Freeze-dried nuclei remained capable of developing into pronuclei even after 12 mo of storage at 4 o C. The level of DNA synthetic activity in the sperm (male) pronucleus was comparable to that in the egg (female) pronucleus. Sperm nuclei that had been stored in 100% ethanol, 100% methanol, or chloroform-methanol (2:1) mixture for 20 days were also capable of developing into pronuclei