Renal amino acid excretion and aging

The urinary excretion and serum concentration of amino acids were studied in 62 healthy individuals aged 15 to 70 years. In elderly subjects (61-70 years), it was found that renal amino acid clearance per 100 ml GFR (fractional excretion, FE) rose significantly in the following amino acids: CYS, VAL, MET, ILE and LEU. Since the serum concentrations of these amino acids showed no significant changes, but the GFR was reduced, it can be concluded that the raised FE of these amino acids was due to a decrease in their effective tubular reabsorption. A significant correlation was found between FENa and FE of most amino acids including those mentioned above. The findings support the assumption that changes in tubular Na+ transport probably participate in the changes of tubular amino acid transport in elderly individuals.     

Studies on the amount of aluminum and calcium in urine following aluminum administration with and without amino acids

The evidence implicating aluminum as a neurotoxin is mounting. Research with animals and humans has linked aluminum with neuro-cognitive dysfunction and, in some cases, death. Although the relationship between aluminum intake and Alzheimer's disease is still unclear, some experts have recently issued a strong warning that human exposure to aluminum should be limited. The results indicate that the amount of aluminum decreased in the urine in mice that were administered glycine or glutamic acid together with aluminum ion. In the mice in which the amounts of aluminum decreased in the urine, the amount of calcium conversely increased.