Depletion of the monoamino metabolites of Zoalene during frozen storage.

3-Amino-5-nitro-o-toluamide and 5-amino-3-nitro-o-toluamide, the principal metabolites in the tissues of chickens fed a diet containing Zoalene (3,5-dinitro-o-toluamide), were shown to deplete in frozen liver tissues stored up to 1 year at -20 degrees C, but not at -70 degrees C. A slight loss of 5-amino-3-nitro-o-toluamide also occurred in thigh muscle at -20 degrees C. Evidence is presented that demonstrates that the depletion of the metabolites was partially the result of their transformation to glucopyranosyl derivatives; both the alpha- and beta-anomers of the 5-amino-3-nitro-o-toluamide conjugate were observed in liquid chromatograms of tissue extracts.