Reduction of dietary obesity in aP2-Ucp transgenic mice: mechanism and adipose tissue morphology.
C57BL6/J mice with the expression of the mitochondrial uncoupling protein (UCP) gene from the fat-specific aP2 gene promoter were used to study the mechanism by which the aP2-Ucp transgene affects adiposity and reduces high-fat diet induced obesity. In the transgenic mice, UCP synthesized in white fat was inserted into mitochondria, and oxygen uptake by epididymal fat fragments indicated UCP-induced thermogenesis. The respirometry data, UCP content, cytochrome oxidase activity, and tissue morphology suggested functional involution of brown fat. Despite 25- to 50-fold lower mitochondrial cytochrome oxidase activity in white than in brown fat cells, total oxidative capacity in white and brown adipose tissue is comparable. Appearance of novel small cells in the gonadal fat of the transgenic mice was associated with a higher DNA content than that of the nontransgenic mice. The results prove a potential of transgenically altered mitochondria in white fat to modulate adiposity and energy expenditure and suggest the existence of a yet unidentified site-specific link between energy metabolism in adipocytes and cellularity.
Kopecký
J
J
Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Rossmeisl
M
M
Hodný
Z
Z
Syrový
I
I
Horáková
M
M
Kolárová
P
P
D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000273:Adipose Tissue / Q000201:enzymology / Q000473:pathology*; D002001:Adipose Tissue, Brown / Q000201:enzymology; D000818:Animals; D000941:Antigens / Q000032:analysis; D002352:Carrier Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D004041:Dietary Fats; D003576:Electron Transport Complex IV / Q000276:immunology / Q000378:metabolism; D007473:Ion Channels; D008071:Lipoprotein Lipase / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic / Q000235:genetics*; D024101:Mitochondrial Proteins; D009765:Obesity / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D012333:RNA, Messenger / Q000378:metabolism; D012119:Respiration; D000071256:Uncoupling Protein 1
D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000941:Antigens; D002352:Carrier Proteins; D004041:Dietary Fats; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D000071256:Uncoupling Protein 1; D003576:Electron Transport Complex IV; D008071:Lipoprotein Lipase