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- Title
Divergence in aerobic capacity and energy expenditure influence metabolic tissue mitochondrial protein synthesis rates in aged rats.
- Authors
Franczak, Edziu; Maurer, Adrianna; Drummond, Vivien Csikos; Kugler, Benjamin A.; Wells, Emily; Wenger, Madi; Peelor III, Frederick F.; Crosswhite, Abby; McCoin, Colin S.; Koch, Lauren G.; Britton, Steven L.; Miller, Benjamin F.; Thyfault, John P.
- Abstract
Age-associated declines in aerobic capacity promote the development of various metabolic diseases. In rats selectively bred for high/low intrinsic aerobic capacity, greater aerobic capacity reduces susceptibility to metabolic disease while increasing longevity. However, little remains known how intrinsic aerobic capacity protects against metabolic disease, particularly with aging. Here, we tested the effects of aging and intrinsic aerobic capacity on systemic energy expenditure, metabolic flexibility and mitochondrial protein synthesis rates using 24-month-old low-capacity (LCR) or high-capacity runner (HCR) rats. Rats were fed low-fat diet (LFD) or high-fat diet (HFD) for eight weeks, with energy expenditure (EE) and metabolic flexibility assessed utilizing indirect calorimetry during a 48 h fast/re-feeding metabolic challenge. Deuterium oxide (D2O) labeling was used to assess mitochondrial protein fraction synthesis rates (FSR) over a 7-day period. HCR rats possessed greater EE during the metabolic challenge. Interestingly, HFD induced changes in respiratory exchange ratio (RER) in male and female rats, while HCR female rat RER was largely unaffected by diet. In addition, analysis of protein FSR in skeletal muscle, brain, and liver mitochondria showed tissue-specific adaptations between HCR and LCR rats. While brain and liver protein FSR were altered by aerobic capacity and diet, these effects were less apparent in skeletal muscle. Overall, we provide evidence that greater aerobic capacity promotes elevated EE in an aged state, while also regulating metabolic flexibility in a sex-dependent manner. Modulation of mitochondrial protein FSR by aerobic capacity is tissue-specific with aging, likely due to differential energetic requirements by each tissue.
- Subjects
AEROBIC capacity; MITOCHONDRIAL proteins; PROTEIN synthesis; DEUTERIUM oxide; LIVER mitochondria; LOW-fat diet
- Publication
GeroScience, 2024, Vol 46, Issue 2, p2207
- ISSN
2509-2715
- Publication type
Article
- DOI
10.1007/s11357-023-00985-1