SULFOTRANSFERASE GENE-EXPRESSION IN PRIMARY CULTURES OF RAT HEPATOCYTES

Hepatocyte cultures have been used in pharmacotoxicological studies, a nd sulfotransferases (ST) are important drug-metabolizing enzymes in l iver. The expression of sulfotransferases in hepatocyte cultures has n ot been examined systematically. In the present study, the mRNA levels of different sulfotransferases in male and female rat hepatocytes wer e examined by northern-blot analyses. Various culture conditions such as different matrices (collagen, matrigel, collagen sandwich, or co-cu lture with epithelial cells), medium (Waymouth's MB 752/1 and Modified Chee's Medium) and glucocorticoid supplementation (dexamethasone, 0.1 mu M) were compared. Phenol ST (ST1A1) mRNA levels decreased to about 50% of initial mRNA levels within 10 hr of culture. At 96 hr, ST1A1 m RNA levels were approximately 20% of initial values when cultured on c ollagen, matrigel or co-culture. The two media did not differ in abili ty to maintain ST1A1 mRNA levers in the absence of dexamethasone (DEX) ; however, DEX addition to either medium resulted in ST1A1 mRNA levels greater than 100% of the initial mRNA levers at 96 hr, with the great est increase observed using the matrigel substratum and Chee's medium. In the absence of DEX, the mRNA levers of N-hydroxy-2-acetylaminofluo rene sulfotransferase (ST1C1), estrogen surfotransferase (ST1E2) and h ydroxysteroid surfotransferase (ST-20/21, ST-40/41, ST-60) fell to app roximately 20% of their initial levers within 24 hr, and to less than 5% at 96 hr. The loss of expression of these sulfotransferases was obs erved with all culture conditions. Addition of DEX to the media result ed in ST-40/41 and ST-60 mRNA expression at 20 and 35% of their initia l values, respectively, in cultures maintained on matrigel and Chee's medium at 96 hr. These data suggest that sulfotransferases lose their constitutive expression in hepatocyte culture, but retain their induci bility. Copyright (C) 1996 Elsevier Science Inc.