Sex Differences in Body Composition and Insulin Action in Aging C57BL/6J Mice

Abstract

A paucity of data exists regarding sex‐differences in age‐related obesity and insulin resistance. The purpose of this study was to determine the effects of age and sex on insulin action and body composition in C57BL/6J mice. In aged (AG, 18 months old) male mice, glucose tolerance was diminished compared to young (YG, 6 months old) male mice (Area Under Curve: 95,103±6,818 vs 64,005±2,031, P=0.002). However, there was no age‐related decline in glucose or insulin tolerance in females. Body composition analysis revealed that AG males had significantly greater body mass (42.2±1.9 vs 30.0±0.4 g, P<0.0001), fat mass (18.7±2.0 vs 3.3±0.4 g, P<0.0001), body fat (43.0±3.0 vs 11.0±1.5%, P<0.0001) than YG males. In AG females, body mass (32.8±1.6 vs 26.3±0.9 g, P=0.02) was higher, but fat mass (13.3±2.0 vs 9.5±1.3 g, P=0.24) and body fat (37.8±4.8 vs 35.5±3.8%, P=0.67) were similar when compared to YG females. AG males had significantly higher body mass (42.2±1.9 vs 32.8±1.6 g, P=0.001) and fat mass (18.7±2.0 vs 13.3±2.0 g, P=0.04) compared to AG females; however, body fat (43.0±3.0 vs 37.8±4.8%, P=0.28) was similar. Although aging and obesity are associated with higher levels of oxidative stress, six weeks of treatment with MitoQ, a mitochondrial‐targeted antioxidant, did not reduce adiposity in AG male mice. Surprisingly, when AG male mice survive to 28 months of age, the obesity and insulin resistance that was observed at 18 months of age is reversed. In conclusion, our findings indicate that male mice, but not female mice, develop age‐related obesity and insulin resistance, a process that is reversed in the oldest of old mice.Support or Funding InformationNIA 1R15AG053790‐01This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.