Cryopreservation of wild mouse spermatozoa.
Spermatozoa of wild mice from China, Czechoslovakia, Denmark, India, Japan and Switzerland were frozen and stored at -196 degrees C. After thawing, intact oocytes were inseminated in vitro with relatively high motility frozen-thawed mouse spermatozoa from Czechoslovakia, Denmark and India, while oocytes with a partially dissected zona were inseminated with low motility frozen-thawed spermatozoa from China, Japan and Switzerland. Embryos developing to the 2-cell stage from oocytes fertilized with frozen-thawed spermatozoa were transferred to the oviducts of female recipients on the first day of pseudopregnancy (day when a vaginal plug was confirmed). Successful embryo development to the 2-cell stage was 46 to 67%. Offspring resulted from 17 to 51% of these transferred 2-cell embryos.
Nakagata
N
N
Nippon Institute for Biological Science, Tokyo 198, Japan.
Ueda
S
S
Yamanouchi
K
K
Okamoto
M
M
Matsuda
Y
Y
Tsuchiya
K
K
Nishimura
M
M
Oda
S
S
Koyasu
K
K
Azuma
S
S
Toyoda
Y
Y