PLASMA-MEMBRANE PERTURBATION INDUCED BY ORGANOTINS ON ERYTHROCYTES FROM SALMO IRIDEUS TROUT

Tributyltin chloride and its degradation products monobutyltin and dib utyltin act as water pollutants, owing to the use of tributyltin chlor ide as a biocide in marine paint formulations. These compounds are lip id-soluble and undergo bioaccumulation and bioconcentration. Salmo iri deus trout erythrocytes were studied to evaluate the possible effects of these compounds on freshwater fish, which could be exposed to long- term effects due to bioaccumulation or organotins. Data showed that tr ibutyltin increases the haemolysis rate, starting at 10 mu M, while di butyltin has a scant protective effect at each concentration tested. S imilar studies were performed in the presence of carbon monoxide (CO), which is protecting against membrane oxidation. In these conditions a ll the organotins tested induced an increase in the haemolysis rate. T hese results suggest that the consequence of auto-oxidation of Hb coul d condition the effects of some organotin compounds. Steady-state fluo rescence of probes embedded in the lipidic part of the membrane was us ed to evaluate the modifications induced by organotins to the physico- chemical state of phospholipids.