Rat hepatic bile acid sulfotransferase: enzyme response to androgens and estrogens

Abstract

Rat liver bile sulfotransferase activity can be divided into a fraction that reacts with a monoclonal antibody (PK1B) and another fraction that does not. This work was performed to analyze the known response of hepatic bile acid sulfotransferase activity to androgens and estrogens by determining the effect of treatment on the proportion of bile acid sulfotransferase activity that possessed the epitope for PK1B monoclonal antibody. Activity in treated animals was further characterized by high-performance liquid chromatography (HPLC) analysis following purification by PK1B-immunoadsorption chromatography. The results indicate that estrogens and androgens affect the subset of enzyme activity that has the PK1B epitope more than the population that does not. HPLC demonstrates that increases and decreases in activity that follow treatment with androgens and estrogens are mirrored by the proportion of the PK1B-reactive protein that exhibits a relative molecular weight (Mr) greater than 170,000. Radial immunodiffusion assays of hepatic supernatant using a polyclonal antibody raised against PK1B-reactive bile acid sulfotransferase show that changes in specific activity that follow treatment are the result of changes in enzyme protein concentration.