Consequences of renal mass reduction on amino acid and biogenic amine levels in nephrectomized mice

Amino acid and biogenic amine changes were investigated in nephrectomized m ice ten days postsurgery. Uremic mice exhibited changes in amino acid conce ntrations in plasma, urine and brain. Particularly plasma methionine, citru lline and arginine levels were significantly enhanced in nephrectomized mic e compared to controls whereas serine was decreased. Urinary excretion of m ethionine, citrulline and alanine was higher in nephrectomized mice compare d to controls whereas many amino acids were increased in brain of nephrecto mized mice. Brain and urinary amino acid changes were more pronounced in th e 75% than in the 50% nephrectomized mice. Brain norepinephrine and dopamin e and its metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid were significantly increased whereas serotonin was decreased comparing the 75% nephrectomized mice to the sham-operated mice. This study demonstrates that at very early stages of renal insufficiency, specific amino acid and b iogenic amine changes occur in plasma, urine and brain. These alterations m ight depend qualitatively and quantitatively on the degree of functional re nal mass reduction.