Concentrative transport of purine nucleosides in brush border vesicles of the rat kidney

Abstract

Nephrotoxicity has been reported in humans and in animals during treatment with nucleosides. We described recently a Na⁺ gradient-dependent concentrative transport of adenosine in brush border vesicles isolated from the cortex of the rat kidney. The results of the present study suggest that that transport is shared by other purine nucleosides. The transport of adenosine is inhibited by several purines at micromolar concentrations. The transports of deoxyadenosine, of inosine and of guanosine are concentrative in the presence of a Na⁺ gradient and they are inhibited by adenosine. We conclude that there exists a concentrative system for reabsorption of various purine nucleosides in the proximal tubule. The transport of nucleosides is non-concentrative in all other cell types studied so far. The concentrative capacity of the transport of nucleosides in the kidney might explain the particular sensitivity of that organ during treatment with nucleosides.