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Volume 19, Issue 4, Pages 213-219

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

Filiz Korkmaz,1 Halil Kirbiyik,2 and Feride Severcan3

1Materials Science Engineering, Atılım University, Ankara 06836, Turkey
2Department of Physics, Middle East Technical University, Ankara 06531, Turkey
3Department of Biology, Middle East Technical University, Ankara 06531, Turkey

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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.