Preliminary characterization of pyruvate uptake by one-cell ovine embryos

Pyruvate uptake was measured by a noninvasive method on a total of 59 individual one-cell ovine embryos. Uptake was measured over a 4-h period in Whitten's medium containing 1.0 mM glucose and either 0.0 mM, 0.33 mM, 0.67 mM or 1.0 mM sodium pyruvate. Glucose uptake was also assessed to determine the effect of altering pyruvate concentration on glucose uptake. Embryos incubated in medium containing 1.0 mM or 0.67 mM pyruvate showed average uptake values of 20.36 and 5.00 pmoles per embryo per 4 h, respectively. In contrast, when pyruvate concentrations were 0.0 mM and 0.33 mM, the embryos released an average of 24.60 and 10.40 pmoles pyruvate per embryo per 4 h. Uptake or release of pyruvate was found to vary linearly with concentration level. Increasing pyruvate concentration resulted in a significant decrease in glucose uptake.