Urinary p-tyramine in hereditary tyrosinemia: II. Origin of urinary p-tyramine.
1. A patient with hereditary tyrosinemia (tyrosinosis) was given oral loads of p-tyramine and tyrosine with and without medication (neomycin) to investigate the respective roles of intestinal bacteria and tissues in accounting for the origin of urinary p-tyramine. 2. The excretion of a high circulating level of p-tyramine following an oral load of p-tyramine in a patient with hereditary tyrosinemia (tyrosinosis) was as conjugated p-hydroxyphenylacetic acid (p-HPAA) and conjugated p-tyramine. 3. Both intestinal bacterial activity and tissue decarboxylation appeared to account for urinary p-tyramine in this patient following an oral load of tyrosine. 4. Sterilization of the gut by oral neomycin and a second load of oral tyrosine further supported a predominate role for tissue decarboxylation in the origin of urinary p-tyramine. 5. The data suggested that a major route of tyrosine metabolism in man may be via tissue decarboxylation of tyrosine.
D015111:4-Hydroxyphenylpyruvate Dioxygenase / Q000172:deficiency*; D000284:Administration, Oral; D000293:Adolescent; D000592:Amino Acid Metabolism, Inborn Errors / Q000652:urine*; D004032:Diet; D005260:Female; D006801:Humans; D009355:Neomycin / Q000627:therapeutic use; D010105:Oxygenases / Q000172:deficiency*; D014439:Tyramine / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine*; D014443:Tyrosine / Q000378:metabolism
D014443:Tyrosine; D010105:Oxygenases; D015111:4-Hydroxyphenylpyruvate Dioxygenase; D009355:Neomycin; D014439:Tyramine