Effects of 2-G exposure on temperature regulation, circadian rhythms, and adiposity in UCP2/3 transgenic mice.
Altered ambient force environments affect energy expenditure via changes in thermoregulation, metabolism, and body composition. Uncoupling proteins (UCPs) have been implicated as potential enhancers of energy expenditure and may participate in some of the adaptations to a hyperdynamic environment. To test this hypothesis, this study examined the homeostatic and circadian profiles of body temperature (T(b)) and activity and adiposity in wild-type and UCP2/3 transgenic mice exposed to 1 and 2 G. There were no significant differences between the groups in the means, amplitudes, or phases of T(b) and activity rhythms at either the 1- or 2-G level. Percent body fat was significantly lower in transgenic (5.2 +/- 0. 2%) relative to the wild-type mice (6.2 +/- 0.1%) after 2-G exposure; mass-adjusted mesenteric and epididymal fat pads in transgenic mice were also significantly lower (P < 0.05). The data suggest that 1) the actions of two UCPs (UCP2 and UCP3) do not contribute to an altered energy balance at 2 G, although 2) UCP2 and UCP3 do contribute to the utilization of lipids as a fuel substrate at 2 G.
Fuller
P M
PM
Section of Neurobiology, Physiology, and Behavior, Division of Biological Sciences, School of Medicine, University of California, Davis, California 95616-8519, USA.
Warden
C H
CH
Barry
S J
SJ
Fuller
C A
CA
D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001823:Body Composition; D001831:Body Temperature; D001833:Body Temperature Regulation / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D022202:Chromosomes, Artificial, Bacterial; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D018471:Hypergravity; D007473:Ion Channels; D026901:Membrane Transport Proteins; D051379:Mice; D008822:Mice, Transgenic; D024101:Mitochondrial Proteins; D009043:Motor Activity; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012016:Reference Values; D014475:Uncoupling Agents; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
D002352:Carrier Proteins; D007473:Ion Channels; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; C000604389:UCP2 protein, human; C000604392:UCP3 protein, human; C000604390:Ucp2 protein, mouse; C000604393:Ucp3 protein, mouse; D014475:Uncoupling Agents; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3