title: The effect of ouabain on placental transport of 86Rb.
abstract: Human placental fragments concentrate 86Rb 10--20-fold during a two-hour incubation period. Inhibition of ouabain is dose-dependent, reaching 90 + per cent at a concentration of 5 x 10(-5) M. The clearance index of 86Rb across the perfused human placenta is 0.34 +/- 0.08, comparing to previously reported indices for Na22 and Cl36 of 0.28 and 0.41, respectively. Ouabain in concentrations up to 5 x 10(-5) M had no detectable effect on transfer across the placenta. The clearance index of ouabain is low, averaging 0.07 in 3 experiments. 3H-ouabain is not detectably bound to albumin or placental homogenate.
mesh_terms: D002713:Chlorine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D010042:Ouabain / Q000494:pharmacology*; D010477:Perfusion; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011868:Radioisotopes / Q000378:metabolism*; D012413:Rubidium / Q000378:metabolism*; D012979:Sodium Radioisotopes / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013997:Time Factors
chemical_list: D011868:Radioisotopes; D012979:Sodium Radioisotopes; D002713:Chlorine; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium