In vivo regulation of adipose tissue protein kinase by adenosine 3',5'-monophosphate mediated glucagon stimulation.

The cytochrome P-450 content of primary hepatocyte cultures was maintained at levels close to those found $\text{in vivo}$ by using a defined medium containing testosterone, thyroxine, hydrocortisone, estradiol, glucagon, insulin, linoleic acid and oleic acid. Using these cultures, [¹⁴C]aflatoxin B₁, a potent liver carcinogen, was metabolized primarily to water-soluble metabolites. In agreement with $\text{in vivo}$ results, aflatoxin M₁ was the only nonpolar metabolite detected. In addition, a significant portion of radioactivity was covalently bound to cell constituents. These results suggest that primary hepatocyte cultures may be a good model of the liver for studying the metabolism and mechanism of action of toxic chemicals.