Mussel exposure to tributyltin (TBT): response of membrane-bound ATPase activities.

The effect of exposure of mussels (Mytilus galloprovincialis) to tributyltin (TBT) on membrane-bound ATPase activities involved in key metabolic processes (ionic regulation, mitochondrial energy production) was investigated. Attention was paid also to possible changes in the lipid matrix, expecially membrane fatty acid composition. The complex pattern of ATPase responses, mirrors possible interactive effects between TBT and its metabolic partially dealkylated derivatives. Different responses in the tissues under study may be related to the different membrane features as well as to the different speciation of organotins in different body districts. The fatty acid composition of microsomal and mitochondrial membranes was poorly influenced by TBT exposition with the exception of 22:6n-3 level, significantly decreased in gill mitochondria of TBT-exposed mussels. The 22:6n-3 reduction can be related to a cardiolipin loss from mitochondrial membranes, as this fatty acid amounts to approximately 70-80% of total fatty acids in mussel cardiolipin.