Research Paper Volume 8, Issue 10 pp 2370—2391

Figure 3. Metabolic rate differed between the age groups in male, but not female mice. (A) Female mice of all ages had similar metabolic rates during the dark (=active) phase. (B) During the dark phase, 4-month -old male mice had higher metabolic rates on average than 20, 28 and 32-month-old males (p = 0.025, p < 0.0001, p < 0.0001 respectively). 20-month-old males also had higher mass-specific metabolic rates compared to 28 and 32-month-olds (p = 0.002 in both cases). 28 and 32- month-old males did not differ (p > 0.999). (C) Female mice of all ages had similar metabolic rates during the light (=inactive) phase (p = 0.943). (D) During the light phase, 4-month -old male mice had higher metabolic rates on average than 28 or 32-month-old males (p = 0.033, p = 0.012, respectively), as did 20-month-old males (p = 0.002, p = 0.010, respectively). 28 and 32- month-old males did not differ from one another (p > 0.999). Post-hoc tests subject to Bonferroni correction for multiple comparisons. Metabolism sample size: Females n = 20, 20, 26 and 26 for 4, 20, 28 and 32 months; Males n = 17, 21, 29 and 28 for 4, 20, 28 and 32 months.