['L-Arginine supplementation was found to have a reno-protective effect in different models of chronic renal failure (CRF) in spite of normal plasma levels. Experiments were designed to determine if changes in glomerular uptake of arginine occur in 5/6 nephrectomized rats as a model of CRF. Renal function and glomerular uptake of radiolabeled arginine {[3H] L-arginine} was measured in sham operated, 5/6 nephrectomy, and right nephrectomy rats. Renal failure and proteinuria was found in the CRF animals only. Arginine uptake by glomeruli harvested from rats with CRF was significantly lower than that by glomeruli from sham operated and unilateral nephrectomy rats.'] Is glomerular arginine transport attenuated in chronic renal failure in rats?