| 16728205 |
Saeki K, Nagao Y, Kishi M, Nagai M: Developmental capacity of bovine oocytes following inhibition of meiotic resumption by cycloheximide or 6-dimethylaminopurine. Theriogenology. 1997 Nov;48(7):1161-72.
This study was conducted to assess the fertilizability and developmental capacity of bovine oocytes which had been maintained in meiotic arrest by either a protein synthesis inhibitor, cycloheximide (CHX), or an inhibitor of serine/threonine protein kinases, 6-dimethylaminopurine (6-DMAP). Both CHX and 6-DMAP reversibly prevented nuclear maturation of nearly all oocytes for 24 h. After the reversal of arrest, CHX-treated oocytes could be successfully matured and fertilized. They developed to the blastocyst stage at slightly lower rates than oocytes cultured without inhibition for 22 h prior to sperm addition but at higher rates than those incubated in a medium containing no inhibitors for 46 h prior to fertilization. Oocytes inhibited by CHX for 48 h matured and fertilized normally but failed to develop into blastocysts. Even though 6-DMAP-treated oocytes completed meiosis I after removal from the drug, the rates of fertilization and blastocyst formation were lower than for untreated oocytes or CHX-treated oocytes. Effects of adding FSH and/or estradiol-17 beta (E (2)) during CHX-inhibition for 24 h were also examined. Embryos from oocytes treated with CHX and E (2) or with CHX and FSH + E (2) developed into blastocysts at similar rates as the controls. Further development of inhibited oocytes was examined by transferring blastocysts derived from oocytes inhibited by CHX with FSH and E (2) for 24 h to recipient heifers. Two calves were obtained following transfer. These results indicate that CHX-inhibited oocytes retain developmental competence, while 6-DMAP-inhibited oocytes after the reversal of arrest have reduced capacities for fertilization and further development. The addition of FSH and E (2) during CHX-inhibition improves development to the blastocyst stage of the oocytes that are capable of initiating and maintaining pregnancy after embryo transfer to recipient animals. |
81(1,1,1,1) |