Fate of 7,12-dimethylbenz(a)anthracene absorbed from the rat intestine and transported in chylomicrons.

Chylomicrons obtained from the thoracic duct of rats fed [3H]7,12-dimethylbenz(a)anthracene (DMBA), a polycyclic aromatic hydrocarbon, were infused intravenously into rats with bile fistulas. Over 17 hr, 55.9 +/- 3.2% (mean +/- SEM) of the radioactivity was recovered in bile and 6.7 +/- 0.5% in urine. Minor amounts were deposited in liver, kidneys and epididymal fat pads. Injection of DMBA in ethanolic solution gave a similar pattern, while biliary DMBA metabolites resulted in higher recovery in urine and lower recovery in fat. In conclusion, the major part of chylomicron DMBA is rapidly excreted via the biliary route, while a fraction is probably retained in adipose tissue.