A study of angiotensin II binding sites in human placenta, chorion, and amnion.
The binding of tritiated angiotensin II to 20,000 x g particulate tractions of human placenta, chorion, and amnion was investigated. Binding to particles from the three tissues reached equilibrium within 10 minutes at 29 degrees C and was displaced by the addition of 1,000-fold excess of unlabeled angiotensin II. Scatchard analysis of the data showed that two classes of binding sites were present in the placental preparation. For the high-affinity site, values of 9 x 10(-9) M and 300 fmoles/mg of protein were obtained for the dissociation constant and the binding capacity, respectively. There was little specific binding in chorion and amnion.
D000650:Amnion / Q000032:analysis*; D000804:Angiotensin II / Q000378:metabolism*; D002823:Chorion / Q000032:analysis*; D005260:Female; D006801:Humans; D010920:Placenta / Q000032:analysis*; D011247:Pregnancy; D011945:Receptors, Angiotensin / Q000032:analysis*; D011956:Receptors, Cell Surface / Q000032:analysis*
D011945:Receptors, Angiotensin; D011956:Receptors, Cell Surface; D000804:Angiotensin II