Energy restriction reduces metabolic rate in adult male Fisher-344 rats.
Energy restriction, without malnutrition, prolongs the maximum life span of laboratory rodents. A reduction in metabolic rate has been proposed as a potential mechanism for increased longevity. The present study examines changes in metabolic rate of adult rats after a 6-wk period of energy restriction. Two groups (n = 6) of 6-mo-old male Fisher-344 rats were studied. Restricted rats were pair-fed a diet equivalent in vitamins and minerals but restricted to 60% of energy consumed by rats eating ad libitum. Average and basal metabolic rates were measured by direct calorimetry over a 24-h period without food. Fat mass and lean body mass were determined by NMR spectroscopy. After 6 wk of restriction, when expressed per kilogram of lean body mass the average metabolic rate was reduced by 14% and basal metabolic rate by 12% compared with the ad libitum diet rats (P < or = 0.01). Reduction of metabolic rate did not seem to be a transient effect of chronic energy restriction in mature rats.
Gonzales-Pacheco
D M
DM
Department of Health Promotion, University of New Mexico, Albuquerque 87131.
Buss
W C
WC
Koehler
K M
KM
Woodside
W F
WF
Alpert
S S
SS
D000818:Animals; D001481:Basal Metabolism / Q000502:physiology; D001823:Body Composition; D002151:Calorimetry; D002149:Energy Intake / Q000502:physiology*; D008136:Longevity; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008660:Metabolism / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344