Related Experiment Video

Updated: Jun 21, 2026

Measurement of Insulin- and Contraction-Stimulated Glucose Uptake in Isolated and Incubated Mature Skeletal Muscle from Mice
08:01

Measurement of Insulin- and Contraction-Stimulated Glucose Uptake in Isolated and Incubated Mature Skeletal Muscle from Mice

Published on: May 16, 2021

A-769662 activates AMPK beta1-containing complexes but induces glucose uptake through a PI3-kinase-dependent pathway

Jonas T Treebak1, Jesper B Birk, Bo F Hansen

  • 1Molecular Physiology Group, Copenhagen Muscle Research Centre, Department of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark.

American Journal of Physiology. Cell Physiology
|August 7, 2009
PubMed

Insights

The compound A-769662 activates beta1-containing AMPK complexes in skeletal muscle. However, it increases glucose uptake via a PI3-kinase pathway, suggesting off-target effects that may limit its use in AMPK research.

Area of Science:

  • Metabolic regulation
  • Skeletal muscle physiology
  • Pharmacology

Background:

  • 5'-AMP-activated protein kinase (AMPK) is a key regulator of cellular metabolism.
  • A-769662 is a known activator of AMPK, particularly in skeletal muscle.
  • The specific biological effects of A-769662-induced AMPK activation in skeletal muscle remain largely uncharacterized.

Purpose of the Study:

  • To investigate the effects of A-769662 on glucose uptake in skeletal muscle.
  • To determine the relationship between A-769662-induced AMPK activation and glucose uptake.
  • To elucidate the signaling pathways involved in A-769662's effects on skeletal muscle metabolism.

Main Methods:

  • Incubation of soleus and extensor digitorum longus (EDL) muscles from 129S6/sv and C57BL/6 mice.
  • Measurement of glucose uptake in response to varying concentrations of A-769662.
  • Assessment of AMPK complex activation and phosphorylation of key signaling proteins (Akt, acetyl-CoA carboxylase).
  • Investigation of phosphatidylinositol 3 (PI3)-kinase activity and inhibition studies with wortmannin.

Main Results:

  • A-769662 dose-dependently activated AMPK beta1-containing complexes in both soleus and EDL muscles.
  • Glucose uptake was significantly increased only in soleus muscles from 129S6/sv mice at higher A-769662 concentrations.
  • A-769662 increased Akt phosphorylation and PI3-kinase activity, which were inhibited by wortmannin, while AMPK phosphorylation remained unaffected.
  • These findings indicate a dissociation between AMPK activation and glucose uptake stimulation by A-769662.

Conclusions:

  • A-769662 activates beta1-containing AMPK complexes in skeletal muscle.
  • The observed increase in glucose uptake is mediated by a PI3-kinase-dependent pathway, not directly by AMPK activation.
  • A-769662 exhibits off-target effects in intact skeletal muscle, potentially limiting its utility for studying AMPK's role in muscle metabolism.

More Related Videos

Isolation of Primary Mouse Hepatocytes for Nascent Protein Synthesis Analysis by Non-radioactive L-azidohomoalanine Labeling Method08:04

Isolation of Primary Mouse Hepatocytes for Nascent Protein Synthesis Analysis by Non-radioactive L-azidohomoalanine Labeling Method

Published on: October 23, 2018

Glucose Uptake Measurement and Response to Insulin Stimulation in In Vitro Cultured Human Primary Myotubes08:03

Glucose Uptake Measurement and Response to Insulin Stimulation in In Vitro Cultured Human Primary Myotubes

Published on: June 25, 2017

Related Concept Videos

cAMP-dependent Protein Kinase Pathways01:25

cAMP-dependent Protein Kinase Pathways

Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...
Insulin: The Receptor and Signaling Pathways01:28

Insulin: The Receptor and Signaling Pathways

Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
GPCRs Regulate Adenylyl Cylase Activity01:09

GPCRs Regulate Adenylyl Cylase Activity

Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...