Abstract
Enzymohistochemical demonstrations of phosphatases, nonspecific esterase and dehydrogenases in differentiated 8-16 cell eggs which appear 70 to 76 hours after ovulation were carried out in this study. For comparison, 8-cell eggs before differentiation and early blastocysts were observed.
Phosphatases: In 8-cell eggs, alkaline phosphatase activity was intense, adenosine-tri-phosphatase moderate, and acid phosphatase weak. Acid and alkaline phosphatases were spread throughout the cytoplasm, while adenosine-tri-phosphatase localized near the cell membrane. Concerning differentiated eggs and blastocysts, acid phosphatase activity was much stronger in inner cells than in trophoblasts, while the activities of alkaline and adenosine-tri-phosphatase showed no local differences. With all the eggs from the three stages, the presence of glucose-6-phosphatase and 5' nucleotidase was not confirmed, because they were nonspecific to the substrates.
Nonspecific estearse: In eggs at every stage, nonspecific esterase activity was weak, though it spread throughout the cytoplasm. In differentiated eggs and blastocysts, its activity was stronger in trophoblast than in inner cells.
Dehydrogenases: In 8-cell eggs, activities of malate and lactate dehydrogenases were moderate, while those of other dehydrogenases were weak or feeble. In differentiated eggs and blastocysts, local changes were observed in the strength of some dehydrogenase activities; activities of malate, β-hydroxybutyrate, lactate and a-glycerophosphate dehydrogenases were stronger in trophoblasts than in inner cells of such eggs. As for succinate, isocitrate, glucose-6-phosphate, glutamate dehydrogena-ses, the strength of their activities showed no differences between inner cells and trophoblasts.
