Interaction of dehydroepiandrosterone with phospholipid membranes: an infrared spectroscopy investigation

The interaction between dehydroepiandrosterone (DHEA) and its sulfate metabolite (DHEA-S) with deuterated dimirystoylphosphatidylcholine (DMPC-d54) was investigated by FTIR spectroscopy. DHEA, as cholesterol, induces some conformational order in the liquid-crystalline phase of DMPC-d54. Attenuated total reflectance (ATR) measurements performed on oriented DMPC-d54/steroids samples have shown that in the gel phase, the acyl chains of DMPC-d54 become more normal to the bilayer surface in the presence of DHEA or cholesterol. On the other hand, DHEA-S increases the number of gauche conformers along the hydrocarbon chains of DMPC-d54. No evidence for the presence of hydrogen bond was found between both steroids and the 13C labeled carbonyl group of hydrated DMPC.