Increased size and endocrine area of pancreatic islets after 10 weeks of treatment with EGCG or rosiglitazone. Light microscopic appearance of pancreatic islets immunostained for insulin in control db/db mice and db/db mice receiving dietary supplementation with 1% (w/w) EGCG or 0.0021% (w/w) rosiglitazone (Rosi) for 10 weeks. Islets are immunostained for insulin (brown) and original magnification was 200 x. Bars represent mean ± SEM for 9 mice in each group. For islet size, * denotes P < 0.001, and for endocrine area P < 0.01, for chance differences vs controls using one-way ANOVA in conjunction with Dunnett's multiple comparison test.