The 4-O-methylation pathway of catecholamines: search for an in vivo production of 3-hydroxy,4-methoxyphenylglycol (iso-MHPG).
The existence of 3-hydroxy,4-methoxyphenylglycol in biological fluids has been investigated. 4-Hydroxy,3-methoxy-phenylglycol (MHPG) and 3-hydroxy,4-methoxyphenylglycol (iso-MHPG) have been separated from each other by gas-liquid chromatography of their heptafluorobutyryl derivatives, using an electron capture detector procedure. Urines of normal subjects, of patients with secreting nervous tissue tumors and human cerebrospinal fluids were analyzed. Iso-MHPG was never detected, with the exception of trace amounts in one urinary sample from a patient with a peculiarly high excretion of MHPG. It is concluded that norepinephrine is probably not 4-O-methylated in vivo, contrary to dopamine which is known to lead, at least to a small extent, to 4-O-methylated metabolites.
D002849:Chromatography, Gas; D004298:Dopamine / Q000378:metabolism*; D006018:Glycols / Q000378:metabolism*; D006801:Humans; D008734:Methoxyhydroxyphenylglycol / Q000134:cerebrospinal fluid / Q000378:metabolism* / Q000652:urine; D008745:Methylation; D009380:Neoplasms, Nerve Tissue / Q000652:urine; D009638:Norepinephrine / Q000378:metabolism
D006018:Glycols; D008734:Methoxyhydroxyphenylglycol; D004298:Dopamine; D009638:Norepinephrine