RT-PCR quantification of ubiquitination gene transcripts in rat islets exposed to 2.8 or 16.7 mmol/l glucose for 2 h (A) or 24 h (B). RT-PCR quantification of ubiquitination gene transcripts in rat islets exposed to 2.8 or 16.7 mmol/l glucose for 2 h (A) or 24 h (B). Quantification of each gene is relative to an internal control gene amplified in the same tube. For each gene, 100% was assigned to the expression level in islets at 2.8 mmol/l glucose. After 24-h culture in high glucose, parkin, UbcH5, and β-TRCP expression was reduced. n = 4 experiments, with 3–4 replicates. **P < 0.01, *P < 0.05. María D. López-Avalos et al. Diabetes 2006;55:1223-1231 ©2006 by American Diabetes Association