Calorie restriction and exercise affect AMPK differently across muscle cell compartments in older male rats
In skeletal muscle from 24–25-month-old male rats, eight weeks of calorie restriction raised AMPK and ACC phosphorylation in whole lysates but not in the tested cytosol, nucleus or mitochondria fractions; one swim session raised AMPK phosphorylation in the cytosol and ACC phosphorylation in whole lysates and all three fractions. [1]
Automatic summary · not editorially reviewed
The key findings
The study examined AMPK signaling in skeletal muscle from aged male rats aged 24–25 months. [1]
Rats received either eight weeks of calorie restriction at 65% of ad libitum intake or a single swim-exercise session. [1]
Calorie restriction raised AMPK and ACC phosphorylation in whole lysates but not in the three tested fractions. [1]
The source at a glance
- Study type / format
- Animal study (abstract)
- Population / context
- Skeletal muscle from aged male rats aged 24–25 months.
- Summary based on
- Study abstract
- Original publication
- June 23, 2026
AMPK compartments in aged rat muscle
The study examined AMPK signaling in skeletal muscle from aged male rats aged 24–25 months. AMPK is described as an energy sensor present in several subcellular compartments, including the cytosol, nucleus and mitochondria. The authors note that how physiologically relevant interventions affect AMPK localization in muscle is not well understood, especially in older age.
Supporting source [1]
Calorie restriction versus one swim session
Rats underwent either eight weeks of calorie restriction, consuming 65% of ad libitum intake, or a single swim-exercise session. Phosphorylation of AMPK and its substrate ACC, plus abundance of AMPK subunits (α1, α2, β1, β2, γ1, γ3), were measured by immunoblotting in whole muscle lysates and in cytosolic, nuclear and mitochondrial-enriched fractions obtained by differential centrifugation.
Supporting source [1]
Different compartment patterns for the two interventions
Calorie restriction increased AMPK and ACC phosphorylation in whole lysates but not in the three tested fractions, suggesting activation in other, currently unidentified compartments. Exercise increased AMPK phosphorylation in the cytosol and ACC phosphorylation in whole lysates and all three fractions. AMPK-γ1 abundance was greater in the mitochondrial-enriched fraction after calorie restriction than in ad libitum muscle. The authors describe strikingly different activation patterns and call for future research on compartment-specific roles.
Supporting source [1]
How to interpret this
This is an abstract; the full text was not reviewed. Findings come from male rats aged 24–25 months and cannot be generalized to humans. The abstract reports no sample size per group and no effect sizes. The calorie-restriction result is limited to the fractions tested, and the authors state activation may occur in unidentified compartments. The work is described as a foundation for future research, not as established human benefit.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Wang H, Hao J, Bae JH, Cartee GD. · europepmc.org · June 23, 2026