Identification of brown fat and mechanisms for energy balance in the marsupial, Sminthopsis crassicaudata

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dc.contributor.authorHope, P.
dc.contributor.authorPyle, D.
dc.contributor.authorDaniels, C.
dc.contributor.authorChapman, I.
dc.contributor.authorHorowitz, M.
dc.contributor.authorMorley, J.
dc.contributor.authorTrayhurn, P.
dc.contributor.authorKumaratilake, J.
dc.contributor.authorWittert, G.
dc.date.issued1997
dc.description.abstractThe presence of brown adipose tissue (BAT) in marsupials is controversial because attempts to identify mitochondrial uncoupling protein (UCP) have been unsuccessful. Sminthopsis crassicaudata is a small nocturnal marsupial with an interscapular pad of adipose tissue. Electron microscopy revealed this tissue to have characteristics typical of BAT. GDP binding and UCP detection by immunoblot confirmed BAT. Expression of UCP was increased by cold exposure. When animals were placed from 28 to 15 degrees C, body temperature (Tb) decreased by 1.7 degrees C within 30 min and a further 1.0 degree C by 90 min (P < 0.001) before stabilizing at these lower levels. When animals were returned to 28 degrees C, Tb increased within 30 min (P < 0.001) and returned to basal by 120 min. When animals were maintained at 15 degrees C with ad libitum food for 12 days, Tb (P < 0.05), tail width (P < 0.04), and O2 consumption (P < 0.01) all decreased. The respiratory quotient increased (P < 0.001), indicating a change from fat to carbohydrate utilization. Food intake was unchanged, and body weight increased on day 1 (P < 0.01) before returning to baseline on day 3, remaining stable thereafter. These data suggest that although BAT is present in the marsupial S. crassicaudata, it may not be necessary for thermogenesis, at least in the short term. S. crassicaudata utilizes a plasticity in Tb and a change in substrate utilization to maintain energy balance and body composition without the need for an increase in metabolic rate or food consumption and without the need for torpor.
dc.description.statementofresponsibilityPerdita J. Hope , Diana Pyle , Christopher B. Daniels , Ian Chapman , Michael Horowitz , John E. Morley , Paul Trayhurn , Jaliya Kumaratilake, and Gary Wittert
dc.identifier.citationAmerican Journal of Physiology. Regulatory Integrative and Comparative Physiology, 1997; 273(1):R161-R167
dc.identifier.doi10.1152/ajpregu.1997.273.1.r161
dc.identifier.issn0363-6119
dc.identifier.issn2163-5773
dc.identifier.orcidHorowitz, M. [0000-0002-0942-0306]
dc.identifier.orcidMorley, J. [0000-0001-6444-2965]
dc.identifier.orcidKumaratilake, J. [0000-0001-5904-7629]
dc.identifier.orcidWittert, G. [0000-0001-6818-6065]
dc.identifier.urihttp://hdl.handle.net/2440/5310
dc.language.isoen
dc.publisherAmerican Physiological Society
dc.rightsCopyright © 1997 the American Physiological Society
dc.source.urihttp://ajpregu.physiology.org/content/273/1/R161
dc.subjectMitochondria
dc.subjectAdipocytes
dc.subjectAnimals
dc.subjectMarsupialia
dc.subjectMice
dc.subjectBody Weight
dc.subjectCarrier Proteins
dc.subjectIon Channels
dc.subjectMembrane Proteins
dc.subjectMitochondrial Proteins
dc.subjectGuanosine Diphosphate
dc.subjectMicroscopy, Electron
dc.subjectFeeding Behavior
dc.subjectAcclimatization
dc.subjectEnergy Metabolism
dc.subjectOxygen Consumption
dc.subjectBody Temperature Regulation
dc.subjectModels, Biological
dc.subjectMale
dc.subjectAdipose Tissue, Brown
dc.subjectCold Temperature
dc.subjectUncoupling Protein 1
dc.titleIdentification of brown fat and mechanisms for energy balance in the marsupial, Sminthopsis crassicaudata
dc.typeJournal article
pubs.publication-statusPublished

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