Animal studies, using different models of kidney dysfunction/failure, e.g., 5/6 nephrectomized animals (model of chronic renal failure), ischemia/reperfusion-induced acute renal failure (model of acute renal failure), cisplatin- or glycerol-induced acute renal failure provide evidence that dysfunctional state of the organ is characterized by downregulation of uptake carriers (Oats) and increased function of efflux transporters (Mrp2, Mrp4, and P-gp) [89,93,94,95]. This evidence concerns the gene ABCC4 and acute kidney injury.