Organ differences in microsomes and cytosol metabolism of Aflatoxin B1 in piglets

In order to delineate the features of aflatoxin B1 (AFB1) metabolism in various organs of piglets, in vitro metabolism of AFB1 by microsomes and cytosol of the various piglet organs was studied. The AFB1 was converted efficiently to AFP1 by the kidney microsomes. A less efficient metabolism was noted from the AFB1 to AFQ1, AFM1, and aflatoxicol (AFL) in the various organs. The microsomal ability to form AFB1-DNA adduct was higher in liver when compared to the other organs. The cytosolic glutathione-S-transferase activity to convert AFB1-epoxide to AFB1-glutathione conjugate product was relatively higher in the liver and the small intestine. The reductase activity to convert AFB1-dialdehyde to AFB1-dialcohol was similar in all the organs. The results suggest that the variation in susceptibility to the aflatoxin among different organs is attributable mainly to the organ differences in cytochrome P450 activity to form AFB1-epoxide.