Abstract
The activity of prostaglandin dehydrogenase in hamster eggs at the preimplantation period was investigated by a histochemical method using prostaglandin (PG) A1, PGA2, PGE1, PGE2, PGF1α and PGF2α as the substrates.
Eggs were obtained at different developmental stages: unfertilized eggs 2 hours, sperm-penetrated eggs 4 hours, pronuclear eggs 11 hours, 2-cell eggs 32 hours, 4-cell eggs 52 hours, 8-cell eggs 65 hours and blastocysts 76 hours each after ovulation. Histochemical demonstration of the enzyme was carried out by the NISSEN and ANDERSEN method with a slight modification. The composition of the medium was 0.3 mM of substrate, 0.75 mM of NAD, 0.075 mM of nitro-BT, and 0.1 M phosphate buffer solution at pH 8.0, so as to the whole amount of the medium was to be 1 ml.
The enzyme activity was found in unfertilized, sperm-penetrated, pronuclear, 2-cell, 4-cell and 8-cell eggs, but not in blastocysts. The activity varied only slightly among these developmental stages. From such results, it seems that PG metabolism is present in hamster eggs at the unfertilized through 8-cell stages, but is absent in the blastocysts.
