Fig. 4
Effect of concentration of inducers on HO-1 mRNA induction in Hepa 1c1c7 cells after 6-hr exposure
Compounds used were 13, 25, or 100 µM tert-butylhydroquinone (Compound 1); 19, 38, 75, or 150 µM 1,2-dithiole-3-thione (Compound 2); 0.25, or 1.0 µM sodium arsenite (Compound 4); 12.5, 25, 50, or 100 µM trans-4-phenylbut-3-en-2-one (Compound 5); 100 µM 2,3-dimercapto-1-propanol (Compound 6); 1.3, 2.5, 5, or 10 µM HgCl2 (Compound 7); 1.25, 5, or 10 µM benzyl isothiocyanate (Compound 8); 25, 50, or 125 nM phenylarsine oxide (Compound 9). The concentrations refer to the bars from left to right, respectively. The mRNA was quantitated by Northern blots, and the values were normalized to the 18S rRNA amounts on the same blots. Note the logarithmic scale of the relative RNA ratios.