Effect of acetaldehyde on binding of prostaglandins by receptors of liver plasma membranes.

Rat liver plasma membranes possess a single class of high affinity binding sites for the carbonyl-containing prostaglandins PGE2 and PGE1. The specificity of the binding sites is confirmed by the effective competition of the corresponding unlabeled PGs with 3H-PGs for binding sites on receptors. The modification of liver plasma membranes by acetaldehyde drastically decreases the density of the binding sites, leaving unaffected the affinity of receptors. To bind PGF2 alpha, liver plasma membranes have two types of binding sites, strong and weak ones. The alkylation of membranes by acetaldehyde does not essentially change the PGF2 alpha binding parameters. It is suggested that the protective effect of PGs in alcoholic liver injury occurs by their competition with acetaldehyde for binding sites on specific PG-binding receptors of liver plasma membranes.