Urinary excretion of the enantiomers of 1-methyl-1,2,3,4-tetrahydro-beta-carboline in unequal abundance implies enzymatic metabolism in man.
1-Methyl-1,2,3,4-tetrahydro-beta-carboline, a condensation product of tryptamine and acetaldehyde, is one of the neuropharmacologically active alkaloids in mammals. Its enantiomers excreted in human urine were independently analyzed by gas chromatography-negative ion chemical ionization mass spectrometry. Mass fragmentograms of the racemic 1-methyl-1,2,3,4-tetrahydro-beta-carboline offered two peaks with (S)-(-)- and (R)-(+)-configurations which were eluted in this retention order. When the racemic tetradeuterated 1-methyl-1,2,3,4-tetrahydro-beta-carboline was orally administered to a human subject, the urinary tetradeuterated enantiomers were found to be of unequal abundance. The deuterated (R)-(+)-1-methyl-1,2,3,4-tetrahydro-beta-carboline was predominantly excreted in human urine about 3-times over the deuterated (S)-(-)-one. The stereoselective difference in the urinary excretion of 1-methyl-1,2,3,4-tetrahydro-beta-carboline administered exogenously implies that it is enzymatically metabolized, but not that its biosynthesis is associated with an enzymatic reaction.
Tsuchiya
H
H
Department of Dental Pharmacology, Asahi University School of Dentistry, Gifu, Japan.
Todoriki
H
H
Hayashi
T
T
D000284:Administration, Oral; D002243:Carbolines / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine*; D004798:Enzymes / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D013237:Stereoisomerism
D002243:Carbolines; D004798:Enzymes; C009777:2-methyltryptoline