Characterization of prostaglandin E2 receptors in lung of guinea pigs

By means of radioligand binding assay. the prostaglandin E2 receptors in lung of guinea pig were identified. The results presented in this paper demonstrated the existence of high affinity binding sites for PGE2 in the membranes prepared from lung of guinea pig. The speciality of the binding was verified by the saturability. reversibility, low KD value (3.4 nmol/L) and stereoselectivity. Both the affinity and the binding capacity of the receptors were decreased by preincubating the membranes with N-ethylmaleimide. This result suggests that the existence of SH group is necessary for the binding site of PGE2 receptor. The fact that the activity of adenylate cyclase was increased by incubating the membranes with PGE2 shows the possibility of a similar mechamsm of transmembrane signalling to other receptor systems such as beta-adreno-ceptor-adenylate cyclase.