[Binding of various polycyclic aromatic hydrocarbons (PAH) by plasma albumin and blood cells]

We have studied in vivo and in vitro partition of pyrene, fluoranthene and benz(a)anthracene (BaA) between blood cells and plasma or phosphate buffer pH 7.4 and their binding to bovine serum albumin. The level of PAH in blood and plasma was determined in rats after i.v. administration of pyrene, fluoranthene and BaA in dose 20 mg/kg by gas chromatography method. In vitro 20 micrograms of PAH was added to blood samples or blood cell suspension. These samples were incubated at 37 degrees C. After 1 hr the concentration of PAH in blood cell and plasma or buffer was determined. The data indicate that whole pyrene and fluoranthene are distributed to blood cells. 39% of BaA in whole blood is present in blood cells and 56.9% in plasma. Plasma protein binding of PAH were determined by gel filtration 0.4 cm3 of PAH-protein solution was given on a Sephadex column. PAH binding parameters were obtained from simple linear regression of Scatchard plots of the data. In a albumin solution (0.4%) the number of binding sites was 2 for BaA, 3 for pyrene and 11 for fluoranthene. The binding constants for BaA, fluoranthene and pyrene were 0.17; 0.71 and 1.11 mol-1 X 10(4), respectively.