PPARγ Ligands Increase Expression and Plasma Concentrations of Adiponectin, an Adipose-Derived Protein

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FIG. 4.
FIG. 4.

Effect of TNF-α on expression and secretion of adiponectin in 3T3-L1 adipocytes. Dose effect of TNF-α on the adionectin mRNA level (A) and the secreted amount in media (B) are shown. After differentiation-induction on day 7, 3T3-L1 cells were treated with indicated concentrations of TNF-α for 24 h. One nanogram per milliliter of TNF-α corresponds to 57 pmol/l. Total RNAs (5 μg) were subjected to Northern blotting and quantified as described in the legend of Fig. 3A. The amount of adiponectin secreted into media was measured by quantitative Western blotting. Inset shows a representative picture of Northern and Western blotting that was quantified. After differentiation-induction on day 7, 3T3-L1 cells were treated with or without 1 ng/ml TNF-α and 10 μmol/l TGZ for 24 h (C). Total RNAs (5 μg) were subjected to Northern blotting and quantified as described in the legend of Fig. 3A. Effects of TNF-α on the adiponectin promoter activity were analyzed as described in Fig. 3E (D). Adiponectin-luciferase and pRL-SV40 vector were cotransfected into day 7–differentiated 3T3-L1 cells. For each 12-well dish, 1 μg adiponectin-luciferase and 10 ng pRL-SV40 were used. Three hours after transfection, an equal amount of DMSO or DMEM containing TZDs or TNF-α was supplemented to medium. At 48 h after transfection, cells were harvested, and firefly and Renilla luciferase reporter activity was measured as described in research design and methods. Adiponectin-luciferase (firefly) activity was normalized by pRL-SV40 Renilla luciferase activity. Values are means ± SE from three independent experiments. *P < 0.01 compared with control values.

This Article

  1. Diabetes vol. 50 no. 9 2094-2099