Interaction of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)-ethane with liposomal phospholipids

The influence of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and several other pesticides on the physical state of membrane phospholipids was investigated using model lipids. The thermal dependence of fluorescence intensity of the probe parinaric acid in dipalmitoylphosphatidylcholine liposomes and lipid vesicles of mixed composition were recorded. DDT was incorporated into the liposomal bilayer. The insecticide lowered the phase transition temperature and broadened the temperature range of the transition. The effects were concentration-dependent. The results may be interpreted as a sort of blurred and facilitated phase transition of bilayer lipids caused by intercalation of DDT between fatty acyl chains of membrane phospholipids.