[Role of interstitium in the regulation of renal tubular solute transport].

The physiological significance of the renal interstitium is reviewed with special reference to solute transport. The renal tubules and vasculatures participate in essential parts of the nephron functions. The renal interstitium, interposing among these structures, regulates solute transport across the renal tubules. In the renal cortex, changes in the interstitial pressure modulate the proximal tubular fluid reabsorption via paracellular shunt pathways. In the renal medulla, the interstitium may play an important role in the lateral diffusion of solutes and water, contributing to the mechanisms of urine concentration, as well as, medullary potassium recycling and ammonia excretion.