ABSTRACT
The high renal blood flow can be responsible for the delivery of large quantities of any substance present in the blood. The kidney might be in a position to accumulate large quantities of the chemical if it can readily cross the various biological membranes. The accumulation by passive means of large quantities of potentially nephrotoxic compounds might lead to high intracellular concentrations which could disrupt renal function. A xenobiotic so concentrated might become capable of exerting undesirable effects on the tubular membranes, or at the very least be present in a sufficiently high concentration which could facilitate the diffusion of that substance into the renal tubular cells. The ability of the kidney to transport certain substrates from the tubular fluid to the blood and others from the blood to the tubular fluid is perhaps the most important single feature of renal cells. Renal physiologists and pharmacologists have used p-aminohippurate to measure renal plasma flow for decades.
