FIGURE 8.

LXR activation increases Pdx-1 protein content in the nucleus of human islets. Nuclear (A) or total protein (B) was isolated from ∼1000 human islets incubated in media containing 25 mm glucose in the presence or absence of 1 μm TO-901317 for 18 h. Pdx-1 protein levels on immunoblot were normalized to actin protein levels. All data are shown as the mean ± S.E. (n = 4). Groups were compared using a t test. *, data indicate statistical difference (p < 0.05) versus human islets incubated without TO-901317. C, 2 μg of human islet nuclear extract was used for each EMSA reaction with or without 5 μl of preimmune serum or anti-Pdx-1 antiserum and separated by 5% polyacrylamide gel. EMSA was performed using the A3 element of the human INS promoter containing the sequence CTG GTT AAG ACT CTA ATG ACC CGC TGG TCC TG. For competition experiments, an unlabeled probe of the same sequence was added at 100 or 200 times the concentration of labeled probe. Data shown are representative of three independent experiments.