Gender-related differences in morphology and thermogenic capacity of brown adipose tissue mitochondrial subpopulations.
To investigate the possible existence of a gender dimorphism in the morphology and functionality of brown adipose tissue (BAT) mitochondrial subpopulations, we obtained three mitochondrial fractions - heavy, medium and light - by differential centrifugation. Electron microscopic analysis was carried out and mitochondrial protein content, cytochrome c oxidase and ATP synthase activities, mitochondrial DNA content and UCP1 protein levels were measured in each mitochondrial fraction. Female rats showed a greater mitochondrial size than males, with a different distribution pattern of the subpopulations. These differences were accompanied by higher oxidative and thermogenic capacities and a higher protein content in female rat BAT. This tissue also showed a greater tendency to respiratory chain uncoupling, as well as a close coordination between the oxidative, phosphorylative and thermogenic processes. These differences were found in the heavy subpopulation but not in the light one. Our results demonstrate that female rat BAT shows a highly differentiated mitochondrial pool, with the heavy mitochondrial subpopulation as the main responsible for the greater thermogenic activity of this tissue. In addition, it seems that there is a differential regulation of the mitochondrial growth cycle between genders in BAT, which leads to enhanced thermogenic capacity in female rat mitochondria.
Justo
Roberto
R
Departament de Biologia Fonamental i Ciències de la Salut, Institut Universitari d'Investigació en Ciències de la Salut (IUNICS), Universitat de les Illes Balears, Cra. Valldemossa km 7.5. E-07122-Palma de Mallorca, Spain.
Frontera
Margalida
M
Pujol
Esperanza
E
Rodríguez-Cuenca
Sergio
S
Lladó
Isabel
I
García-Palmer
Francisco José
FJ
Roca
Pilar
P
Gianotti
Magdalena
M
D002001:Adipose Tissue, Brown / Q000378:metabolism* / Q000648:ultrastructure*; D000818:Animals; D002352:Carrier Proteins / Q000032:analysis; D004272:DNA, Mitochondrial / Q000032:analysis; D005260:Female; D007473:Ion Channels; D008297:Male; D008565:Membrane Proteins / Q000032:analysis; D008928:Mitochondria / Q000378:metabolism / Q000648:ultrastructure*; D024101:Mitochondrial Proteins; D025261:Mitochondrial Proton-Translocating ATPases / Q000032:analysis; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D012727:Sex Characteristics; D022722:Thermogenesis; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D004272:DNA, Mitochondrial; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; C000604373:Ucp1 protein, rat; D000071256:Uncoupling Protein 1; D011451:Prostaglandin-Endoperoxide Synthases; D025261:Mitochondrial Proton-Translocating ATPases