Animal characteristics of lean and diabetic ZDF rats after 2 weeks of treatment with water or 30, 100 or 300 mg/kg body weight/day metformin (MET30, MET100 and MET300, respectively).

Data is represented as mean ± SD (n = 6 per group). Fasting plasma glucose (ANOVA: P<0.001) and insulin (ANOVA: P<0.01) were significantly higher in diabetic animals compared with lean animals, independent of treatment regimen. For body weight, the interaction between genotype and treatment was significant and a pairwise analysis of differences is provided by Bonferroni-corrected two-sided unpaired t-tests: ## P<0.01, ### P<0.001 when compared with lean animals of the same treatment regimen.