Ouabain‐sensitive fluid accumulation and ion transport by rabbit blastocysts.

Abstract

By incubating 6-day post-coitum (pc) blastocysts in medium supplemented with either 20 mm-sucrose or 10 mM-KCl, the trophectoderm of the blastocyst prevented the concentration of K in the blastoccoele fluid rising to external concentrations. The concentrations of K in the blastocoele fluid were maintained predominantly by leakage of K from the trophoblast cells into the blastocoele and by ouabain-sensitive transport of K into the trophoblast cells from the blastocoele fluid. Exposure of blastocysts to ouabain on the juxtacoelic, but not abcoelic, surface of the trophectoderm may inhibit blastocoele fluid accumulation.