title: Calcium uptake by placental plasma membrane vesicles.
abstract: The placental plasma membrane vesicles are capable of accumulating up to 190 mM Ca2+. This is 24-fold higher than the external Ca2+ concentration. This process is dependent on ATP hydrolysis by the placental Ca2+-ATPase. The Pi/Ca ratio is dependent on the external Ca2+ concentration, and reaches the value of 2 at 10 mM Ca2+. Phosphate (5 mM) can double Ca2+ uptake when measured in the presence of 5 mM Ca2+. Mg2+ increased Ca2+ uptake only at low Ca2+ concentrations, and had no significant effect at 5 mM Ca2+.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006801:Humans; D008274:Magnesium / Q000494:pharmacology; D010710:Phosphates / Q000494:pharmacology; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy
chemical_list: D010710:Phosphates; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium