Methodology for Measurement of 6-Phosphogluconate Dehydrogenase Activity in Fresh Rat Ovum

Abstract

In order to survey the relationship between metabolic activity and developmental ability of fresh mammalian single ovum, we modified an enzymatic cycling method in the present study. We measured 6-phosphogluconate dehydrogenase activity (6PGD) in fresh 1-cell rat ova to examine the effect of pH on 6PGD activity. As a result, 6PGD activity in phosphate buffer solution (PBS) (-) (pH 7.3) and 1.75mM substrate was the highest; i.e, the activity was 166.2±39.9 × 10^-11 mol/ovum/hr (mean±SE). In the new system, PBS (-) (pH 7.3) and 1.75mM substrate were used instead of Tris-HCl (pH 8.0). The activity of 6PGD in rat 8-cell embryos was 101.1±54.6 × 10^-11 mol/embryo/ hr by this method, and 66.7% (4/6) of the embryos developed to blastocysts following measurement of 6PGD activity.