FGF21 and diabetic kidney disease: The combined treatment of FGF21 with insulin further improves various parameters, including blood glucose, HbA1c, oral glucose tolerance tests (OGTT), renal function, liver function, blood lipid levels, histopathological alterations, oxidative stress (OS), and advanced glycation end-products (AGEs) in mice with diabetic kidney disease (DKD), compared to insulin or FGF21 administered alone (56).