
TY  - JOUR
A1  - Edwards, J. L. 
A1  - Powell, A. M. 
A1  - Rexroad Jr, C. E. 
T1  - Alkaline phosphatase activity in bovine oocytes and preimplantation embryos as affected by removal of the zona pellucida and culture medium constituents
JF  - Reproduction, Fertility and Development
JO  - Reprod. Fertil. Dev.
Y1  - 2003
VL  - 15
IS  - 5
SP  - 285
EP  - 292
KW  - 
UR  - https://doi.org/10.1071/RD03025 
N2  - The aims of the present study were: (1) to characterize alkaline phosphatase (AP) activity in bovine oocytes and embryos with intact or removed zona pellucida (ZP); and (2) to evaluate the effect of culture medium constituents on AP activity. Alkaline phosphatase activity in non-matured and matured oocytes was most evident nearest the plasma membrane and perivitelline space. In more than 90&#37; of two- to 16-cell embryos, AP activity was observed in the perivitelline space and at blastomere contacts. In blastocysts, AP activity was localized to the trophectoderm. Only after immunodissection was AP activity detected in the inner cell mass. Removal of the ZP by pronase or mechanical means reduced AP activity. Alkaline phosphatase activity was detected in evacuated ZP after mechanical removal. Specific constituents comprising the embryo culture medium altered AP activity. Alkaline phosphatase activity was reduced in eight- to 16-cell embryos and evacuated ZP cultured in CR1aa + 0.4&#37; bovine serum albumin compared with embryos cultured in CR1aa alone or embryos co-cultured on a monolayer of Buffalo rat liver cells in the presence of 10&#37; fetal bovine serum. The presence of AP activity at blastomere contacts and in evacuated ZP limits its usefulness as a marker for the differentiation of embryonic cells comprising the early cleavage-stage embryo. 
ER  -

