FIGURE 3.

Growth factors and insulin stimulate HMGR expression in keratinocytes. HaCaT keratinocytes were starved for 24 h and subsequently treated with (a) EGF (10 ng/ml), (b) TGF-α (10 ng/ml), (c) a combination of cytokines (2 nm IL-1β and TNF-α), or (d) insulin (2 μg/ml) for the indicated time periods. Induction of HMGR mRNA expression was assessed by RNase protection assay. 1000 counts of the hybridization probe were used as a size marker. Simultaneous hybridization against GAPDH was used as a loading control (upper panels). A quantification of HMGR mRNA (x-fold induction) is shown in the lower panels.^*, p < 0.05; #, p < 0.05; n.s., not significant (unpaired Student's t test) as compared with control. Bars indicate the mean ± S.D. obtained from three (n = 3) independent cell culture experiments.