Concentration dependent different action of progesterone on the order, dynamics and hydration states of the head group of dipalmitoyl-phosphatidylcholine membrane

Article type: Research Article

Authors: Korkmaz, Filiz | Kırbıyık, Halil | Severcan, Feride^;

Affiliations: Materials Science Engineering, Atılım University, Ankara 06836, Turkey | Department of Physics, Middle East Technical University, Ankara 06531, Turkey | Department of Biology, Middle East Technical University, Ankara 06531, Turkey

Note: [] Corresponding author. Phone: +90 312 210 5166; Fax: +90 312 210 1289; E-mail: feride@metu.edu.tr.

Abstract: Interactions of progesterone with zwitterionic dipalmitoyl phosphatidylcholine (DPPC) multilamellar liposomes (MLVs) were investigated as a function of progesterone concentration at selected temperatures monitoring both the gel and liquid crystalline phase, by using Fourier Transform Infrared spectroscopy (FTIR). It has been show that the effect of progesterone on membrane dynamics is dependent on progesterone concentration. At 1 mol%, which is close to physiological level, progesterone behaves differently. At this concentration the decrease in dynamics is more noticeable. Additionally a dramatic decrease in the strength of hydrogen bonding in the interfacial region of the bilayer is also observed. When concentration increases up to 12 mol% opposite behaviour is observed at all interactions. Above 12 mol%, progesterone–DPPC interactions shows almost linear plot.

Keywords: DPPC liposome, progesterone, FTIR, membrane fluidity, lipid order

Journal: Spectroscopy, vol. 19, no. 4, pp. 213-219, 2005