Figure 4.

The effects of inflammation and endoplasmic reticulum (ER) stress on insulin-dependent adiponectin (ADN) protein expression, ubiquitination, and degradation. 3T3-L1 adipocytes were treated with the proinflammatory cytokine tumor necrosis factor α (TNFα; 20 ng/mL) or ER stress-inducing agent thapsigargin (Tg, 1 μM) for 24 hours before stimulation with insulin and/or cycloheximide (CHX) for 3 hours. A, ADN protein expression; B, CHX-mediated ADN degradation; and C, ubiquitination of ADN. Values are mean + SEM, n = 6. One-way analysis of variance *P less than .05, **P less than .01.