[The binding of furosemide and ethacrynic acid with different types of biological membranes].

The study was undertaken to examine the effects of furosemide and ethacrynic acid on the fluorescence of 1,8-AHC in the suspension of erythrocytic membranes and lumenal and basolateral membranes of the rat renal epithelium. Ethacrynic acid was demonstrated to decrease probe luminescence in all three types of biological membranes. Furosemide failed to affect 1,8-AHC fluorescence in the suspension of blood ghosts and basolateral membranes of the renal epithelium and enhances probe fluorescence in the suspension of luminal membranes. The constants of binding of diuretics to the biological membranes were calculated. The effects of diuretics on the tryptophan fluorescence of renal epithelial luminal and basolateral membranes were studied in one of the series of experiments. It is suggested that the conformational rearrangements in the renal epithelial basolateral and luminal membranes can occur with ethacrynic acid. Furosemide in a dose of 10(-3) M showed the same effect only against luminal membranes.