Figure 4. mRNA expression levels of enzymes associated with carnitine biosynthesis and carnitine transporter in wild-type (WT) mice (white columns) and MTKO mice (black columns) at 100 weeks of age. (A) Tmlhe gene in kidney; (B) Tmlhe gene, (C) Tha1 gene, (D) Shmt1 gene, (E) Shmt2 gene, (F) Aldh9a1 gene, (G) Bbox1 gene, and (H) Slc22a5 gene in liver. The data are expressed as ratios to the mean values in the WT group. Values are presented as the mean ± SE (n = 3). *P < 0.05 and **P < 0.01.