Characterization of the vasopressin receptor on WRK-1 cells

Specific vasopressin binding to WRK-1 rat mammary tumor cells was assessed and compared with vasopressin-induced alterations in phosphatidylinositol metabolism. Scatchard analysis revealed the presence of two binding sites: a saturable, high affinity site with a dissociation constant of 1 X 10(-9) M and an n of 2700 sites per cell, and a nonsaturable, apparent lower affinity site. The higher affinity site appeared to have V1a specificity and to correlate with vasopressin's ability to stimulate phosphatidylinositol turnover in the cells.