Two-cell stage mouse embryos appear to lack mechanisms for alleviating intracellular acid loads.

摘要: Mouse embryos at the two-cell stage, like other cells, can recover from an intracellular acid-load. Our previous work has shown, surprisingly, that there is no contribution to this recovery by Na+/H+ antiport activity. Here we show similarly not affected inhibition of known pH (pHi) regulatory mechanisms. Specifically, unaffected lack external Na+, anion exchange, or bicarbonate, which eliminates Na(+)-dependent HCO3-/Cl- exchanger as a possible These conditions also eliminate any Na+,HCO3- cotransporter operating relieve acid-loading. Recovery nonspecific inhibitors H(+)-ATPase observations lead conclusion acid-load passive process in mouse embryo. Similarly, mean base-line pHi (6.84) dependent on The exhibit marked alkalinization when exposed Cl(-)-free medium presence bicarbonate. This response eliminated inhibitor exchange and but independent Na+. results indicate probably Na(+)-independent active these presumably functioning alleviate alkaline loads.