Also in studies using an animal model of diabetes, the improvement of oxidative-antioxidant (MDA, CAT, and ferric-reducing properties of plasma (FRAP)) and biochemical parameters (alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and fasting blood glucose (FBG)) as well as histopathological changes (tubular differentiation index, mononuclear immune cells, tunica albuginea thickness, seminiferous tubules diameter, Johnsen's score, spermiogenesis index, Sertoli cell index, and meiotic index) were observed after royal jelly supplementation [116, 117]. Here, GPT is linked to diabetes mellitus.