Acetaldehyde-induced formation of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid in rats.
1-Methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) is one of the metabolites of peak E substance, which, based on epidemiological studies, has been thought to be a possible causative agent of the tryptophan-induced eosinophilia-myalgia syndrome. Acute ethanol and L-tryptophan administration in rats pretreated with cyanamide resulted in the formation of MTCA. Concentrations of MTCA were estimated at 27 ng/g in blood and 33 ng/g in kidneys. Chronic treatment with a liquid diet containing ethanol as 36% of the total calories for 6 weeks increased these levels. MTCA was barely observed in rats that had received acute or chronic ethanol in the absence of cyanamide, or in the cyanamide-tryptophan controls. Cyanamide facilitation of ethanol-dependent MTCA biosynthesis may be due to a potentiation of the blood level of acetaldehyde derived from ethanol. The blood acetaldehyde level in rats that had been acutely treated with cyanamide, ethanol and L-tryptophan was 348 microM, and averaged 503 microM in rats that received the same treatment after chronic consumption of ethanol. In contrast to the above findings, L-tryptophan intake promoted the formation of 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (TCCA) in rats. This is the first report of MTCA in mammalian tissue during tryptophan and ethanol metabolism.
Adachi
J
J
Department of Legal Medicine, Kobe University School of Medicine, Japan.
Ueno
Y
Y
Ogawa
Y
Y
Hishida
S
S
Yamamoto
K
K
Ouchi
H
H
Tatsuno
Y
Y
D000079:Acetaldehyde / Q000097:blood / Q000494:pharmacology*; D000818:Animals; D002243:Carbolines / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine*; D003484:Cyanamide; D004032:Diet; D000431:Ethanol / Q000378:metabolism / Q000494:pharmacology; D005215:Fasting; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014364:Tryptophan / Q000378:metabolism / Q000494:pharmacology
D002243:Carbolines; D000431:Ethanol; D003484:Cyanamide; C038114:1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid; C054910:1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid; D014364:Tryptophan; D000079:Acetaldehyde