Interaction of aflatoxin B2 with rat liver DNA and histones in vivo

The interaction of aflatoxin B2 (AFB2) in vivo with rat liver nuclear macromolecules was examined in an attempt to correlate this binding with biological potency. The incorporation of [3H]AFB2 residues into rat liver histones and DNA was determined 2, 24 and 48 h following administration of a single i.p. dose of 1 mg [3H]AFB2/kg body weight. At each time point, histone H1 and the total histone fraction contained 5--30-fold more [3H]AFB2 moieties than did DNA on a weight basis. Analytical reversed-phase h.p.l.c. of the acid hydrolysis products resulting from AFB2 binding to DNA revealed that 85% of the radioactivity co-chromatographed with the major aflatoxin B1-DNA adduct, 2,3-dihydro-2-(N7-guanyl)-3-hydroxyaflatoxin B1. These studies revealed an apparent correlation between AFB2 derived binding to DNA in vivo in rats and its potency as a toxin and carcinogen in this species.