PDK4 and Hyperglycemia: Notably, the dysregulated genes Cpt1a, Foxo1 and Pdk4 also appeared in the network of top 10 upregulated and downregulated mRNAs (Figs. 4C and 4D), indicating that these mRNAs might associate with hyperglycemia and T2D in GK rats at the age of 3 and 4 weeks.