Change in the structure and permeability of phosphatidylcholine membranes stimulated by prostaglandins

Abstract

The surface pressure and surface potential of a two-dimensional solution of prostaglandin E 1 and its synthetic analog E 1α have been investigated using mixed monolayers in a phosphatidylcholine matrix. The properties of the monolayers, most notably their compressibility, were compared with the proton and glucose permeability of bilayer liposomes containing the same prostaglandins. It was found that the presence of the synthetic prostaglandin in the phospatidylcholine membrane caused a five-fold increase in the proton permeability. This effect is explained in terms of the formation of small two-dimensional domains of prostaglandins. Glucose permeability, however, decreased by two orders of magnitude when synthetic prostaglandin was added to the phosphatidylcholine membrane, possibly because of a decrease in the lateral compressibility of the membrane. Possible causes of this phenomenon are discussed in terms of a dynamic pore model.