TY - JOUR
T1 - Life span extension in mice by food restriction depends on an energy imbalance
AU - Sohal, Rajindar S.
AU - Ferguson, Melissa
AU - Sohal, Barbara H.
AU - Forster, Michael J.
PY - 2009/3
Y1 - 2009/3
N2 - In this study, our main objective was to determine whether energy restriction (ER) affects the rate of oxygen consumption of mice transiently or lastingly and whether metabolic rate plays a role in the ER-related extension of life span. We compared rates of resting oxygen consumption between C57BL/6 mice, whose life span is prolonged by ER, and the DBA/2 mice where it is not, at 6 and 23 mo of age, following 40% ER for 2 and 19 mo, respectively. Mice of the 2 strains that consumed food ad libitum (AL) had a similar body mass at the age of 4 mo and consumed similar amounts of food throughout the experiment; however, the body weight subsequently significantly increased (20%) in the C57BL/6 mice but did not increase significantly in the DBA/2 mice. The resting rate of oxygen consumption was normalized as per g body weight, lean body mass, organ weight, and per mouse. The resting rate of oxygen consumption at 6 mo was significantly higher in AL DBA/2 mice than the AL C57BL/6 mice for all of the criteria except organ weight. A similar difference in AL mice of the 2 strains was present at 23 mo when resting oxygen consumption was normalized to body weight. Resting oxygen consumption was lowered by ER in both age groups of each strain according to all 4 criteria used for normalization, except body weight in the C57BL/6 mice. The effect of ER on resting oxygen consumption was thus neither transient nor age or strain dependent. Our results suggest that ER-induced extension of life span occurs in the mouse genotype in which there is a positive imbalance between energy intake and energy expenditure.
AB - In this study, our main objective was to determine whether energy restriction (ER) affects the rate of oxygen consumption of mice transiently or lastingly and whether metabolic rate plays a role in the ER-related extension of life span. We compared rates of resting oxygen consumption between C57BL/6 mice, whose life span is prolonged by ER, and the DBA/2 mice where it is not, at 6 and 23 mo of age, following 40% ER for 2 and 19 mo, respectively. Mice of the 2 strains that consumed food ad libitum (AL) had a similar body mass at the age of 4 mo and consumed similar amounts of food throughout the experiment; however, the body weight subsequently significantly increased (20%) in the C57BL/6 mice but did not increase significantly in the DBA/2 mice. The resting rate of oxygen consumption was normalized as per g body weight, lean body mass, organ weight, and per mouse. The resting rate of oxygen consumption at 6 mo was significantly higher in AL DBA/2 mice than the AL C57BL/6 mice for all of the criteria except organ weight. A similar difference in AL mice of the 2 strains was present at 23 mo when resting oxygen consumption was normalized to body weight. Resting oxygen consumption was lowered by ER in both age groups of each strain according to all 4 criteria used for normalization, except body weight in the C57BL/6 mice. The effect of ER on resting oxygen consumption was thus neither transient nor age or strain dependent. Our results suggest that ER-induced extension of life span occurs in the mouse genotype in which there is a positive imbalance between energy intake and energy expenditure.
UR - http://www.scopus.com/inward/record.url?scp=62749131214&partnerID=8YFLogxK
U2 - 10.3945/jn.108.100313
DO - 10.3945/jn.108.100313
M3 - Article
C2 - 19141702
AN - SCOPUS:62749131214
SN - 0022-3166
VL - 139
SP - 533
EP - 539
JO - Journal of Nutrition
JF - Journal of Nutrition
IS - 3
ER -