Fasting increases gene expressions of uncoupling proteins and peroxisome proliferator-activated receptor-gamma in brown adipose tissue of ventromedial hypothalamus-lesioned rats.
Uncoupling proteins (UCPs) are supposed to be involved in diet-induced thermogenesis. Their activities are usually elevated by feeding and reduced by fasting in normal animals. To investigate whether fasting affects the expression of UCPs mRNA in brown adipose tissue (BAT) of bilateral ventromedial hypothalamus (VMH)-lesioned rats, we determined the gene expression of UCP1, UCP2 or UCP3 in BAT of VMH-lesioned rats and examined oxygen consumption in these rats under fed or 48-h fasted conditions. Northern blotting revealed no difference in the expression of UCPs mRNA in BAT between VMH-lesioned and sham-operated rats under the fed condition, however, expressions were increased markedly in BAT of VMH-lesioned rats under the fasted condition. Under the fed condition, no difference in oxygen consumption was observed between VMH-lesioned and sham-operated rats. Under the fasted condition, oxygen consumption decreased in both rats, however, it decreased in VMH-lesioned less than in sham operated rats. To explore the mechanism that fasting elevated BAT UCPs mRNA in VMH-lesioned rats, we measured peroxisome proliferator-activated receptor (PPAR)-gamma mRNA and protein in BAT, because PPAR-gamma agonist can elevate UCPs mRNA levels in BAT. Under the fed condition, no differences in the expression of PPAR-gamma mRNA and protein content were observed between in BAT of VMH-lesioned and sham-operated rats. Under the fasted condition, however, both increased in BAT of VMH-lesioned rats. These results suggest that VMH-lesions enhance the gene expression of UCPs in BAT under long-term fasting as a defensive reaction to inhibit the reduction of body temperature through an increase in PPAR-gamma activity.
Kageyama
Haruaki
H
Division of Geriatric Health and Nutrition, National Institute of Health and Nutrition, 162-8636, Tokyo, Japan.
Osaka
Toshimasa
T
Kageyama
Asako
A
Kawada
Teruo
T
Hirano
Tsutomu
T
Oka
Jun
J
Miura
Masakazu
M
Namba
Yoshio
Y
Ricquier
Daniel
D
Shioda
Seiji
S
Inoue
Shuji
S
D002001:Adipose Tissue, Brown / Q000502:physiology*; D000818:Animals; D001835:Body Weight; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005215:Fasting; D005260:Female; D005786:Gene Expression Regulation; D007473:Ion Channels; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D010100:Oxygen / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014475:Uncoupling Agents / Q000378:metabolism*; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3; D014697:Ventromedial Hypothalamic Nucleus / Q000033:anatomy & histology / Q000378:metabolism* / Q000473:pathology
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; C000604373:Ucp1 protein, rat; C000604391:Ucp2 protein, rat; C000604394:Ucp3 protein, rat; D014475:Uncoupling Agents; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3; D010100:Oxygen