Role of Kupffer cells in storage and metabolism of benzo(a)pyrene in the liver.

This study investigates the possible role of Kupffer cells in storage and metabolism of benzo(a)pyrene in the liver. In perfused liver, benzo(a)pyrene (4-120 microM) in 0.3% albumin increased fluorescence (366-->405 mm) on the liver surface in a dose-dependent manner, suggesting that it accumulated in liver tissue. The maximal increase of benzo(a)pyrene fluorescence was diminished by 60% when Kupffer cells were destroyed by gadolinium chloride treatment (10 mg/kg iv). Gadolinium chloride also decreased the yield of isolated nonparenchymal cells by 65%. In frozen sections of livers perfused with 4 microM benzo(a)pyrene for 1 hr, fluorescence was approximately 5 times greater in cells lining the sinusoids than in parenchymal cells. Moreover, yellow-green fluorescent particles were detected in cultured Kupffer cells, but were barely visible in parenchymal and Ito cells, indicating that Kupffer cells actively accumulated benzo(a)pyrene. In contrast to the cell specificity for benzo(a)pyrene accumulation, rates of monooxygenation of benzo(a)pyrene were up to 20-fold higher in isolated parenchymal than in Kupffer cells. In nonparenchymal cells, basal rates of production of benzo(a)pyrene phenols were approximately 50 pmol/10(6) cells/hr. In contrast, rates were approximately 335 pmol/10(6) cells/hr in parenchymal cells. Further, total [3H]benzo(a)pyrene metabolism was approximately 8-fold higher in parenchymal than in nonparenchymal cells. Albumin increased production of benzo(a)pyrene phenols by 3-fold in parenchymal cells, but was without effect in nonparenchymal cells. Pretreatment of rats with gadolinium chloride increased the production of benzo(a)pyrene phenols in perfused liver by > 50%.(ABSTRACT TRUNCATED AT 250 WORDS)