5'AMP activated protein kinase is activated as a consequence of lipolysis and has been shown to play a role in regulating adipose tissue mitochondrial content. Conversely, the inhibition of lipolysis has been reported to potentiate the induction of protein kinase A targeted genes involved in the regulation of oxidative metabolism. The purpose of the current study was to address these apparent discrepancies and to more fully examine the relationship between lipolysis, 5'AMP activated protein kinase, and the beta-adrenergic mediated regulation of gene expression. In 3T3-L1 adipocytes the adipose tissue triglyceride lipase inhibitor, ATGListatin, attenuated the Thr-172 phosphorylation of 5'AMP activated protein kinase by a beta 3 adrenergic agonist (CL 316,243) independent of changes in protein kinase A signaling. Similarly, CL 316,243 induced increases in the Thr-172 phosphorylation of 5'AMP activated protein kinase phosphorylation were reduced in adipose tissue from whole body ATGL deficient mice. Despite reductions in the activation of 5'AMP activated protein kinase, the induction of protein kinase A targeted genes was intact, or in some cases increased. Similarly, markers of mitochondrial content and respiration were increased in adipose tissue from ATGL knockout mice independent of changes in the Thr-172 phosphorylation of 5'AMP activated protein kinase phosphorylation. Taken together our data provides evidence that 5'AMP activated protein kinase is not required for the regulation of adipose tissue oxidative capacity in conditions of reduced fatty acid release.
- Copyright © 2016, American Journal of Physiology - Cell Physiology