SPECIFIC BINDING OF PROSTAGLANDIN-E2 TO MEMBRANE PREPARATIONS FROM HUMAN-SKIN - RECEPTOR MODULATION BY UVB-IRRADIATION AND CHEMICAL-AGENTS

Human skin membranes bind prostaglandin E2 (PGE2) with high affinity (with an apparent dissociation constant, K(d), of 3.14x10-9 M) and specificity. This binding is inhibited by trypsin or heat treatment suggesting that PGE2 receptors have protein components. Exposure of the membranes to ultraviolet irradiation (UVB) resulted in the loss of the membrane binding capacity for PGE2. This UVB-inhibitory effect could be prevented by 5,5'-dithiobis-(2-nitrobenzoic acid), a known protein sulfhydryl-oxidizing agent and α-tocopherol, a known lipid anti-oxidant. These results suggest that UVB-irradiation possibly initiate the reduction of critical protein disulfide groups and the peroxidation of lipids in the membranes, which are essential for the receptor-PGE2 interaction.