{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T10:54:33Z","timestamp":1778237673321,"version":"3.51.4"},"reference-count":37,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2024,9,24]],"date-time":"2024-09-24T00:00:00Z","timestamp":1727136000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NIA","award":["1R15AG053790-01"],"award-info":[{"award-number":["1R15AG053790-01"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The impact of aging on body composition and glucose metabolism is not well established in C57BL\/6J mice, despite being a common pre-clinical model for aging and metabolic research. The purpose of this study was to examine the effect of advancing age on body composition, in vivo glucose metabolism, and skeletal muscle AKT expression in young (Y: 4 months old, n = 7), old (O: 17\u201318 months old, n = 10), and very old (VO: 26\u201327 month old, n = 9) male C57BL\/6J mice. Body composition analysis, assessed by nuclear magnetic resonance, demonstrated O mice had a significantly greater fat mass and body fat percentage when compared to Y and VO mice. Furthermore, VO mice had a significantly greater lean body mass than both O and Y mice. We also found that the VO mice had greater AKT protein levels in skeletal muscle compared to O mice, an observation that explains a portion of the increased lean body mass in VO mice. During glucose tolerance (GT) testing, blood glucose values were significantly lower in the VO mice when compared to the Y and O mice. No age-related differences were observed in insulin tolerance (IT). We also assessed the glucose response to AMPK activation by 5-aminoimidazole-4-carboxamide-1-\u03b2-D-ribofuranoside (AICAR). The change in blood glucose following AICAR administration was significantly reduced in VO mice compared to Y and AG mice. Our findings indicate that lean body mass and AKT2 protein expression in muscle are significantly increased in VO mice compared to O mice. The increase in AKT2 likely plays a role in the greater lean body mass observed in the oldest of old mice. Finally, despite the increased GT, VO mice appear to be resistant to AMPK-mediated glucose uptake.<\/jats:p>","DOI":"10.3390\/ijms251910278","type":"journal-article","created":{"date-parts":[[2024,9,24]],"date-time":"2024-09-24T10:41:47Z","timestamp":1727174507000},"page":"10278","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["The Oldest of Old Male C57B\/6J Mice Are Protected from Sarcopenic Obesity: The Possible Role of Skeletal Muscle Protein Kinase B Expression"],"prefix":"10.3390","volume":"25","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0290-528X","authenticated-orcid":false,"suffix":"IV","given":"Thomas H.","family":"Reynolds","sequence":"first","affiliation":[{"name":"Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Noa","family":"Mills","sequence":"additional","affiliation":[{"name":"Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dakembay","family":"Hoyte","sequence":"additional","affiliation":[{"name":"Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katy","family":"Ehnstrom","sequence":"additional","affiliation":[{"name":"Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alex","family":"Arata","sequence":"additional","affiliation":[{"name":"Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,9,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"766","DOI":"10.1016\/S0140-6736(14)60460-8","article-title":"Global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013: A systematic analysis for the Global Burden of Disease Study 2013","volume":"384","author":"Ng","year":"2014","journal-title":"Lancet"},{"key":"ref_2","unstructured":"Purnell, J. 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