Nanomolar Concentrations of Prostaglandin E1 Induce Changes in the Surface Organization of High-Density Lipoproteins

Incubation of high-density lipoproteins (HDL) with small amounts of the prostaglandin E1 (PGE1) results in mobilization of the spin-label 5-doxylstearic acid incorporated into the HDL surface monolayer as well as in decreased binding of apoprotein A1 antibodies to the HDL surface. These effects are manifested at strikingly low PGE1 concentrations, corresponding to one prostaglandin molecule per 102-103 lipoprotein particles. At the same time, the flotation properties of HDL are not changed in the presence of PGE1. The data are interpreted on the basis of a nonequilibrium model proposed earlier for prostaglandin-lipoprotein interactions (Bergelson, L. D., et al. (1987) Biochim. Biophys. Acta 921, 182-190).