title: Uncoupling protein and its mRNA in brown adipose tissue of newborn rabbits.
abstract: Guanosine diphosphate binding to the uncoupling protein of isolated mitochondria of brown adipose tissue in newborn rabbits was measured as an index of thermogenic activity. The binding was 0.281 +/- 0.022 nmol GDP/mg mitochondrial protein at 1 day of age, 0.214 +/- 0.017 at 3 days, 0.428 +/- 0.038 at 5 days, and 0.208 +/- 0.016 at 7 days. The increase in binding between 3 and 7 days of age suggests that the brown fat has an increased thermogenic capacity at that age. In addition, the potential for synthesis of the uncoupling protein was investigated in 1- to 5-day-old newborn rabbits by probing the total cellular ribonucleic acid for the messenger that codes for uncoupling protein. The amount of uncoupling protein messenger was highest at 1 day of age and declined at least until 5 days of age. Because the amount of uncoupling protein messenger decreased as the GDP binding increased, the results suggest that either the initially translated uncoupling protein was unmasked at about 5 days of age or there was a delay in the incorporation of uncoupling protein into the mitochondrial inner membrane, or both.
authors.affiliation: Department of Biomedical Sciences, University of Guelph, Ont., Canada.
authors.forename: D K
authors.initials: DK
authors.lastname: Rozon
authors.forename: W H
authors.initials: WH
authors.lastname: Harris
authors.forename: A M
authors.initials: AM
authors.lastname: Verrinder Gibbins
mesh_terms: D002001:Adipose Tissue, Brown / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D001833:Body Temperature Regulation; D002352:Carrier Proteins; D005260:Female; D006150:Guanine Nucleotides / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000378:metabolism*; D007473:Ion Channels; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000032:analysis / Q000378:metabolism*; D024101:Mitochondrial Proteins; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D011817:Rabbits; D014475:Uncoupling Agents / Q000235:genetics / Q000378:metabolism*; D000071256:Uncoupling Protein 1
chemical_list: D002352:Carrier Proteins; D006150:Guanine Nucleotides; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D014475:Uncoupling Agents; D000071256:Uncoupling Protein 1; D006153:Guanosine Diphosphate