Expression of the class I
alcohol dehydrogenase (ADH) gene in the rat
hepatoma microcell hybrid cell line, 11-3, was examined. The steady-state level of ADH
mRNA in 11-3 was approximately 2-fold higher than that or rat liver and Fao, the parental cell line of 11-3. Removal of
steroid hormones by
activated charcoal from the serum in which 11-3 cells were maintained resulted in a significant decrease in the level of ADH transcript.
Dexamethasone at a concentration of 1 muM increased the ADH
mRNA content in 11-3 in a time-dependent fashion, up to 48 hr after its addition to cells that had first been deprived of
steroid hormones. In addition, levels of ADH transcript in cells treated with
dexamethasone increased in a dose-dependent manner, and the concentration of
dexamethasone required to achieve half-maximal activation was 5 nM. By using the techniques of reverse transcription and polymerase chain reaction, and by taking advantage of a restriction polymorphism present between the rat and mouse ADH
cDNA, we found that 11-3 contained both the rat and mouse class I ADH transcripts, although the rat sequence accounted for the great majority. Moreover, levels of both rat and mouse class I ADH transcripts increased in a similarly time-dependent manner in cells treated with
dexamethasone. These results indicate that expression of class I ADH gene in 11-3 is high and is regulated by
glucocorticoids, making the cell line an excellent model for the in vitro study of ADH expression.