GPT and diabetic kidney disease: Since liver metabolic function has an important role in the development of diabetic nephropathy, we examined the changes of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), and found that their levels were significantly increased after modeling, and this effect was suppressed by the intervention of FGF21 (Figure 2C).