Deletion of the Fgf21 gene increases the deficiency of glucose metabolism-associated pathway, AKT/GSK-3β/GS in testes of diabetic mice. Testicular tissue was used for Western blot analysis of phosphorylated and total AKT (A), GSK-3β (B), and GS (C). Data are presented as mean ± SD (n = 8). *, P < .05 vs WT-CON; #, P < .05 vs WT-DM; +, P < .05 vs KO-CON; &, P < .05 vs KO-DM.