Labilising effect of suramin on rat kidney lysosomes in vivo

Rat kidney lysosomal membrane damage induced by suramin in vitro and in vivo

The effect of suramin, an acid naphthylamine, on rat kidney lysosomal membrane integrity was studied. Lysosomal particles were incubated with suramin (0.1-0.4 mM) and light scattering behaviour of the mixtures were subsequently measured. There was a significant decrease (P less than 0.005) in the amount of light absorbed in the presence of suramin compared to lysosomal particle suspension alone. This was accompanied by release of acid phosphatase, a lysosomal 'marker' enzyme, into the suspending medium. These effects were reduced in the presence of acetylsalicylic acid, a known lysosomal membrane stabilizer. Administration of suramin to rats resulted in loss of kidney acid phosphatase and lysozyme activities from the tissue. These results indicate labilization of rat kidney lysosomal membrane by suramin molecules both in vitro and in vivo.

Alkaline phosphatase activities following repeated suramin administration in some rat tissues in relation to their functions

The effect of repeated administration of suramin, a trypanocide and filariacide, on the level of alkaline phosphatase activity in some rat tissues and organs was investigated. Daily administration of this drug to rats resulted in a very significant increase in enzyme activity in the kidney and small intestine immediately after the first dose. Activity observed in the liver was not affected until after the third dose when the level was increased. In the heart and the large intestine, administration of the drug did not affect the enzyme activity levels throughout the duration of drug administration. These results suggest that repeated suramin administration may result in very large increases in alkaline phosphatase activity in the tissues and organs which are involved in active transport mechanisms.