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, Kd, of 3.14 X 10(-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-ihibitory effect could be prevented by 5,5'-dithiobis-(2-nitrobenzoic acid), a known protein sulfhydryl-oxidizing agent and alpha-tocopherol, a known lipid anti-oxidant. These results suggest that UVB-irradiation possibly initiate the reduction of critical protein disulfide groups and the peroxication of lipids in the membranes, which are essential for the receptor-PGE2 interaction.