Effect of hyperammonemia on brain amino acids in young and adult ferrets.

Effects of arginine deficiency and hyperammonemia on the brain concentrations of amino acids and urea cycle enzyme activities in young and adult ferrets were investigated. Only young ferrets developed hyperammonemia and encephalopathy immediately after consuming the arginine-free diet. Brain ornithine and citrulline concentrations in young ferrets fed arginine containing diet were significantly lower than those in adult ferrets. Compared to rats and other animals, young and adult ferrets had lower concentrations of brain glutamic acid and glutamine. Unlike in other species, brain glutamine was not elevated in young, hyperammonemic ferrets. Brain arginase and glutamate dehydrogenase activities were significantly increased in young ferrets fed arginine-free diet. Young ferrets provide a useful animal model for investigating the neurotoxicity of acute hyperammonemia.