Plasma membrane perturbation induced by tributyltin chloride on density-separated trout erythrocytes

By using a discontinuous Percoll gradient in the 45-65 % range it is possib le to separate nucleated Salmo irideus erythrocytes in three different dens ity fractions that are related to aging of the cell. The stability to lysis of the erythrocytes obtained from the three layers was examined in the pre sence and in the absence of Bu3SnCl4 (TBTC). The rate of hemolysis in the a bsence of the organotin was nearly the same for the three erythrocyte fract ions. The addition of TBTC to the suspension increased the hemolysis but th e effect depended on the density of the fraction, The change in the hemolys is rate was in the order bottom (B) > middle (M) > top (T), The effect of T BTC on 1,6diphenyl-1,3,5-hexatriene (DPH) steady-state fluorescence anisotr opy was measured in liposomes formed by the lipids extracted from the diffe rent fractions, Com pared with the controls, the DPH anisotropy decrease in the presence of TBTC, Steady-state fluorescence of 2-dimethylamino-6-laury lnaphthalene (Laurdan) was measured to evaluate membrane polarity. The pres ence of TBTC on the same liposomes decreased the generalized polarization ( GP(340)) in the top and middle fractions while it did not change in the bot tom fraction, Copyright (C) 1999 John Wiley & Sons, Ltd.