HDAC9 and type 2 diabetes mellitus: The expression of SIRT1 was reduced in the liver of T2D mice compared to non-diabetic CH mice (1.00±0.05 vs. 1.48±0.10 of CH mice, p<0.05, n = 5–8) and OA treatment induced a 50% increase (p<0.05 vs. T2D mice, Fig. 4A) in the expression of SIRT1 (a Class III HDAC).