SOLUBILIZATION OF OXYTOCIN RECEPTORS IN PORCINE RENAL LLC-PK1 CELL-MEMBRANES

The present studies were undertaken to better characterize the pharmac ological properties of oxytocin receptors (OTRs) of the porcine kidney cell line, LLC-PK1, in their natural membranous environment and after solubilization. In intact membranes, binding of a selective radioliga nd was rapid, reversible, saturable, and of high affinity. High-affini ty agonist binding was reduced by a GTP analogue, suggesting that thes e OTRs are associated with G-protein(s). After solubilization with the zwitterionic detergent CHAPSO, OTRs retained their high affinity for the radioligand and rank order potency for oxytocin analogues, and ago nist binding remained biphasic and GTP sensitive.