The interaction between carcinogenic hydrocarbons and serum lipoproteins.

I t has been established that water-insoluble carcinogens and their metabolic products are transported in the blood following their administration to animals (4). Set~l~i and Ermala found that hydrocarbons, when fed, enter the circulation by a route similar to that of dietary fats (9). These investigators observed fluorescence in chylomicrons in lymph and serum obtained from animals after ingestion of 3,4-benzpyrene. I t has been previously shown that hydrocarbons can be suspended or solubilized in vitro in human or animal serum. Andervont and Lorenz (1) have suspended 1,2,5,6,-dibenzanthraeene in serum by treatment of the latter with an ethereal solution of the hydrocarbon and subsequent evaporation of the solvent. Under these conditions, however, the low-density lipoproteins must have lost most of the neutral lipides and changed their composition (3). Falk, Miller, and Kotin (6) demonstrated tha t human plasma will extract polycyclic hydrocarbons from soot. Wunderly and Pezold (1I) carried out electrophoresis of serum on paper previously saturated with carcinogenic hydrocarbons and found that the compounds moved in association with albumin and a and fi globulins. Chalmers (5) has shown that benzpyrene and other hydrocarbons dissolved in serum in vitro are mainly associated with fi-lipoprotein. In a previous study (3) whole serum and isolated serum lipoproteins were found to combine in vitro with cholesterol and other sterols and steroids. Using a similar method we have incorporated several carcinogens into serum. Some studies on the nature and properties of such solutions are reported in this paper.