In vivo 19F MR spectroscopic study of metabolism of 5-fluorotryptophan in rat liver.
The metabolism of 5-fluorotryptophan in rat liver was examined by in vivo 19F MR spectroscopy. After i.v. injection of 200 mg/kg b.w. of 5-fluorotryptophan the substance was noted immediately as a strong peak, which decreased gradually. Another peak appeared about 40 min after the injection. The chemical shift value of this peak was 1.6 ppm from that of 5-fluorotryptophan. Kynurenine is known to be a major metabolite of tryptophan in the liver. We synthesized 5-fluorokynurenine from 5-fluorotryptophan by ozonolysis. The chemical shift value of 5-fluorokynurenine was confirmed to be coincident with that of the metabolite peak. This strongly suggests that the metabolite peak of 5-fluorotryptophan observed in this study was the 5-fluorokyrurenine signal. We also applied this method for the CCl4-injured liver. In the liver injury group, the metabolite peak appeared slowly and the intensity was low compared to that of the normal group, though the peak of 5-fluorotryptophan decreased similarly as in the normal liver. These results suggest that the decrease of 5-fluorotryptophan is due mainly to the renal excretion, as the injured liver could not metabolize 5-fluorotryptophan.
Harada
M
M
Department of Radiology, School of Medicine, University of Tokushima, Japan.
Nishitani
H
H
Koga
K
K
Miura
I
I
Kido
R
R
D000818:Animals; D002252:Carbon Tetrachloride Poisoning / Q000378:metabolism; D056486:Chemical and Drug Induced Liver Injury; D005461:Fluorine; D008099:Liver / Q000378:metabolism*; D008107:Liver Diseases / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014364:Tryptophan / Q000031:analogs & derivatives* / Q000378:metabolism
D005461:Fluorine; C026927:5-fluorotryptophan; D014364:Tryptophan