title: A method for the assay of conjugated 3,4-dihydroxyphenylglycol, a major noradrenaline metabolite in the rat brain.
abstract: We present the first published procedure for the measurement of endogenous conjugated 3,4-dihydroxyphenylglycol (DOPEG) in the rat brain. Conjugated DOPEG is estimated from brain extracts after enzymic hydrolysis, isolation of hydrolysed DOPEG on alumina, methylation of DOPEG to 3-methoxy-4-hydroxyphenylglycol (MOPEG) and gas chromatographic quantification of MOPEG. The level of conjugated DOPEG in the CNS of rats (65.7 +/- 0.7 ng/g whole brain tissue corrected for recovery) almost equals the level of conjugated MOPEG. The sensitivity of the method is about 6 ng/g brain tissue. After inhibition of monoamine oxidase with clorgyline (30 mg/kg) conjugated DOPEG and MOPEG both disappeared from the brain with a half-life of about 1 h. Turnover calculations indicate that conjugated DOPEG and MOPEG are the two major noradrenaline end-metabolites in the rat brain. The method of estimating conjugated DOPEG also allows the measurement of noradrenaline, dopamine and total MOPEG in an extract from one half of a rat brain.
authors.affiliation: Psychopharmacological Research Laboratory, Dept. E, Sct. Hans Hospital, DK-4000 Roskilde, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Nielsen
authors.forename: C
authors.initials: C
authors.lastname: Braestrup
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D000818:Animals; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry; D002849:Chromatography, Gas; D003010:Clorgyline / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005966:Glucuronidase / Q000378:metabolism; D006868:Hydrolysis; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives* / Q000032:analysis* / Q000138:chemical synthesis / Q000378:metabolism*; D008745:Methylation; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D009097:Multienzyme Complexes / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D013429:Sulfatases / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D008996:Monoamine Oxidase Inhibitors; D009097:Multienzyme Complexes; C023059:glusulase; D008734:Methoxyhydroxyphenylglycol; D013429:Sulfatases; D005966:Glucuronidase; D000537:Aluminum Oxide; D003010:Clorgyline; C010117:3,4-dihydroxyphenylglycol; D009638:Norepinephrine