GPT and fatty liver disease: In addition, plasma AST levels (Figure 2(c)) were not changed in KKAy mice by pioglitazone treatment, but plasma ALT levels were slightly increased from 80.1 ± 5.4 to 95.3 ± 4.6 U/L (Figure 2(d), P < 0.05), which further confirmed the liver lesion due to the augmented hepatic steatosis.