Changes in the protein-lipid interaction in rat liver microsomes after pretreatment of the rat with barbiturates and polycyclic hydrocarbons

1. 1. Liver microsomes were assayed fluorometrically after pretreatment of rats with 3-methylcholanthrene, chrysene and phenobarbital. A difference in the fluorescence was obtained after pretreatment with phenobarbital when ANS fluorescence was combined with variable temperature. 2. 2. UDP Glucuronosyltransferase was solubilized after different pretreatments of the rats using trypsin digestion and digitonin solubilization. It was possible to get more enzyme into solution using 3-methylcholanthrene and chrysene as the inducer. Digitonin did not release as much enzyme after phenobarbital treatment of rats. 3. 3. Differently-acting inducers make changes in the protein-lipid interaction in the membranes. These changes are reflected also in the enzyme activities under in vitro conditions.