The addition of activin A to the medium significantly increased the percentage of bovine presumptive zygotes that developed to the blastocyst stage compared with no addition. The development-enhancing effects of activin A were observed when embryos were exposed to activin A prior to the 9- to 16-cell stage. Activin A increased the number of cells in embryos at the onset of the developmental arrest ('lag-phase') during the 4- to 8-cell stages and shortened the duration of the lag-phase. Activin A may enhance the developmental competence of bovine embryos by improving the developmental kinetics during the early cleavage period. (Lab. of Theriogenology, Department of Pathology and Physiology, TEL +81-298-38-7784)
References:
- Yoshioka, K., and Kamomae, H. : Recombinant human activin A stimulates development of bovine one-cell embryos matured and fertilized in vitro. Mol. Reprod. Dev., 45 :151-156 (1996)
- Yoshioka, K., et al. : Differential patterns of blastulation in bovine morulae cultured in synthetic oviduct fluid medium containing FCS or BSA. Theriogenology, 48 :997-1006 (1997)
- Yoshioka, K., et al. : Activin A and follistatin regulate developmental competence of in vitro-produced bovine embryos. Biol. Reprod., 59 :1017-1022 (1998)
- Yoshioka, K., et al. : Differential expression of activin subunits, activin receptors and follistatin genes in bovine oocytes and preimplantation embryos. Reprod. Fertil. Dev., 10 : 293-298 (1998)
- Yoshioka, K., et al. : Effects of activin A and follistatin on developmental kinetics of bovine embryos: cinematographic analysis in a chemically defined medium. J. Reprod. Fertil., 118 : 119-125 (2000)
