The Effect of Amino Acid Infusion on Partial Pressure of Oxygen in Pelvic Urine of the Rat

It is well known that glomerular filtration rate (GFR) and urinary concentrating ability are reduced with advancing age. However, the precise mechanism of the aging kidney is unknown. Previous studies in this laboratory have demonstrated that changes in insoluble collagen and acid mucopolysaccharides (glycosaminoglycans) content occur during aging in the renal papilla of the human kidney. This evidence suggests that, in the aging kidney, changes occur in the renal medulla in parallel with the renal cortex. One of the causes of the age-related changes in connective tissue of the renal papilla seems to be local hypoxia (Inoue et al., 1970; Inoue, 1979).