The metabolism of deuterium-labelled p-tyramine in man
In recent years interest in the metabolism of p-tyramine in man has been stimulated by its possible role in migraine (Hanington, 1967), in hepatic encephalopathy (Faraj et al., 1976) and in the hypertensive crises experienced by some subjects taking monoamine oxidase inhibitors (Blackwell, 1963). It has also been reported that pressor response to infused tyramine is higher in endogenous depression (Ghose, Turner and Koppen, 1975). A number of studies using unlabelled tyramine (Horowitz et al., 1964; Youdim et al., 1971; Smith and Mitchell, 1974) and 14C-labelled tyramine (Smith, March and Gordon, 1972; Boulton and Marjerrison, 1972; Tacker, Creaven and McIsaac, 1972) have been performed in man. They have revealed that the major pathways of metabolism are oxidation and conjugation and that a small proportion of the administered tyramine is excreted unchanged in the urine.
KeywordsHepatic Encephalopathy Phenylacetic Acid Homovanillic Acid Urinary Acid Endogenous Depression
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