Interactions of Malondialdehyde and 4-Hydroxynonenal with Rat Liver Plasma Membranes and their Effect on Binding of Prostaglandin E₂ by Specific Receptors

Abstract

We investigated effect of aldehydic products of lipid peroxidation, malondialdehyde (MDA) and 4-hydrox-ynonenal (HNE) on prostaglandin (PG) E₂ receptors of liver plasma membranes. The modification of the membranes by MDA diminished PGE₂ binding, decreasing receptor affinity for PGE₂ and receptor density whereas HNE increased PGE₂ binding, enhanced receptor density but did not changed receptor affinity. ESR study showed the decrease of the whole membrane fluidity after modification by MDA whereas HNE lowered membrane fluidity only in the internal zone of lipid bilayer and increased it in the surface area. The possible effects of membrane changes caused by MDA and HNE on PGE₂ receptor parameters are discussed.

Key Words:

• Malondialdehyde
• 4-hydroxynonenal
• prostaglandin receptors
• plasma membranes