GPT and steatosis: The increase in steatosis development was further reflected by slightly increased serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels (Figure 4(e)) and higher hepatic triglyceride levels especially after 24-week HFD treatment (Figure 4(f)) in MxCre/c-Metmut compared to c-Metfl/fl mice.