Synthesis of 14C-ochratoxin A and 14C-ochratoxin B and a comparative study of their distribution in rats using whole body autoradiography.
Methods for preparation of labelled ochratoxin A and B are described. The method for preparation of labelled ochratoxin B involves the synthesis of the azide of ochratoxin beta via the mixed anhydride and subsequent conjugation to labelled phenylalanine to yield 14C-ochratoxin B. The labelled ochratoxins were injected into male Wistar rats and after different survival times they were sacrificed and subjected to whole body autoradiography. The distribution pattern of ochratoxin A in the rat did not differ from that earlier registered for mouse. The previously known, high susceptibility of rats (and not mice) to ochratoxin A-induced cancer could thus not be explained by an accumulation of the toxin in specific cells or organs. The distribution patterns of ochratoxin A and B were almost congruent--the only apparent difference being a much longer retention of the labelled ochratoxin A in the blood compared to ochratoxin B, which was much faster excreted. When analyzing tissue extracts for labelled metabolites only the extracts from the rats injected with ochratoxin B were found to contain easily detectable concentrations, while no metabolites of ochratoxin A were seen.
Breitholtz-Emanuelsson
A
A
Department of Biochemistry and Biotechnology, Royal Institute of Technology, Stockholm, Sweden.
Fuchs
R
R
Hult
K
K
Appelgren
L E
LE
D000818:Animals; D001345:Autoradiography / Q000379:methods; D002250:Carbon Radioisotopes; D002855:Chromatography, Thin Layer; D009793:Ochratoxins / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics; D009928:Organ Specificity / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D014915:Whole-Body Counting / Q000379:methods*
D002250:Carbon Radioisotopes; D009793:Ochratoxins; C000426:5-chloro-8-hydroxy-3,4-dihydro-3-methylisocoumarin-7-carboxylic acid; C025589:ochratoxin A; C045354:ochratoxin B