PGE1 but not PGI2 desensitizes the PGI2 receptor-adenylate cyclase complex in human foreskin fibroblasts.

In intact cells or in membranes prepared from intact cells that were preincubated with PGE1, subsequent PGI2-stimulation is attenuated. Preincubation of cells with PGI2 does not induce desensitization of PGI2-stimulated adenylate cyclase. These data suggest that HFF cells must be constantly exposed to a biologically active prostaglandin for desensitization to occur. The intrinsic chemical lability of PGI2 may be a biochemical protection mechanism against desensitization in cells that normally respond to PGI2.