Skip to main content
. 2012 Jun 1;16(11):1323–1367. doi: 10.1089/ars.2011.4123

FIG. 5.

FIG. 5.

Glucose metabolism and NADH/NAD+. The enzymes, pyruvate dehydrogenase (PDH) and lactate dehydrogenase (LDH), dictate whether glycolysis proceeds to glucose oxidation or the formation of lactate. PDH can be inhibited by fatty acid oxidation (341), c-jun N-terminal kinase (JNK) signaling (480), and hypoxia-mediated upregulation of PDH kinase, which, similar to JNK, phosphorylates and inactivates PDH (386). LDH activity is dependent on the expression of the lactate dehydrogenase A (LDHA) or lactate dehydrogenase B (LDHB) subtypes, which promote either lactate formation or pyruvate formation, respectively. The absence of glucose or other conditions that elevate NAD+ promotes sirtuin (SIRT) deacetylase activity to stimulate respiration, activate glycolytic genes, and increase fatty acid oxidation (219) (not shown in figure).