Brown adipose tissue response to cafeteria diet-feeding involves induction of the UCP2 gene and is impaired in female rats as compared to males.
Noradrenaline-dependent brown adipose tissue (BAT) thermogenesis is activated by the cold and excess energy intake, largely depends on the activity of the uncoupling protein 1 (UCP1), and is mediated mainly through the beta3-adrenoceptor (beta3-AR). We investigated the expression of ucp2, a gene that encodes a putative UCP1-like uncoupling protein, along with that of ucp1 and beta3-ar, in the interscapular BAT (IBAT) of male and female rats chronically fed a cafeteria diet. After 3 months on this diet, male rats attained a 34% excess body mass and showed IBAT hypertrophy and increased IBAT thermogenic potential, in terms of both UCP1 and UCP2 mRNA expression (both by 1.6-fold), UCP1 protein expression (by 1.75-fold) and GDP binding to IBAT mitochondria (by 2.2-fold); female rats attained a larger excess body weight (50%) and their IBAT, although hypertrophied, showed no signs of increased thermogenic potential per gram of tissue. Interestingly, the IBAT of female rats was already activated compared to males. Treatment of mouse brown adipocytes in primary culture with noradrenaline also triggered a dose-dependent increase of the levels of UCP1 mRNA and UCP2 mRNA. Retroregulatory down-regulation of the beta3-AR mRNA levels was found in the two models used. The results support a physiological role for UCP2, along with UCP1, in rodent BAT thermogenesis.
Roca
P
P
Departament de Biologia Fonamental i Ciències de la Salut, Universitat de les Illes Balears, Palma de Mallorca, Spain.
Rodriguez
A M
AM
Oliver
P
P
Bonet
M L
ML
Quevedo
S
S
Picó
C
C
Palou
A
A
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D001833:Body Temperature Regulation; D002352:Carrier Proteins / Q000235:genetics; D004032:Diet; D003576:Electron Transport Complex IV / Q000378:metabolism; D002149:Energy Intake; D005260:Female; D005502:Food; D015870:Gene Expression; D006984:Hypertrophy; D007473:Ion Channels; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D022702:Receptors, Adrenergic, beta-3; D012727:Sex Characteristics; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; D012333:RNA, Messenger; D011943:Receptors, Adrenergic, beta; D022702:Receptors, Adrenergic, beta-3; C000604372:Ucp1 protein, mouse; C000604373:Ucp1 protein, rat; C000604390:Ucp2 protein, mouse; C000604391:Ucp2 protein, rat; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D003576:Electron Transport Complex IV