FIGURE 4.

Growth factors and insulin stimulate HMGR activity in keratinocytes. HaCaT keratinocytes were starved for 24 h and subsequently treated with EGF (10 ng/ml), TGF-α (10 ng/ml), insulin (2μg/ml), or a combination of cytokines (2 nm IL-1β and TNF-α) in the absence or presence of simvastatin (10 μm) for the indicated time periods. HMGR activity was assessed using 3-methyl [3-¹⁴C]glutaryl coenzyme A as substrate. ^**, p < 0.01; ^*, p < 0.05 (unpaired Student's t test) compared with control.Barsindicatethemean±S.D.obtainedfromthree(n=3) independent cell culture experiments.