Effect of sympathetic de-activation on thermogenic function and membrane lipid composition in mitochondria of brown adipose tissue.
Male Long-Evans rats (9 weeks of age) were exposed to cold (5 degrees C) for 10 days. Then, sympathetic de-activation of brown adipose tissue (BAT) was performed either by BAT surgical denervation (Sy) or by warm re-exposure at 28 degrees C (WE) for 4 days. The incidence of the two treatments on thermogenic activity of BAT mitochondrial membranes and their lipid composition was investigated. Sy and WE induced a large decrease in GDP binding on the uncoupling protein (UCP) (43% and 82%, respectively). Several parameters of mitochondrial energization were investigated. Sy and WE substantially decreased UCP-dependent proton conductance (CmH+) over the whole range of protonmotive force. CmH+ showed greater variation than GDP binding. The low basal UCP-independent CmH+ was the same in all groups. Comparison of GDP binding and CmH+ with UCP content which is not modified revealed a masking of both the nucleotide binding site and the proton channel. Sy and WE induced the same increase of phosphatidylcholine to phosphatidylethanolamine ratio (16%) but had opposite effects on fatty acid unsaturation. The results were discussed with reference to functional significance of these variations in BAT mitochondrial thermogenic activity and lipid composition.
Goubern
M
M
Laboratoire d'Adaptation Energétique à l'Environnement, EPHE, Paris, France.
Chapey
M F
MF
Senault
C
C
Laury
M C
MC
Yazbeck
J
J
Miroux
B
B
Ricquier
D
D
Portet
R
R
D002001:Adipose Tissue, Brown / Q000294:innervation / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D003714:Denervation; D006153:Guanosine Diphosphate / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D007473:Ion Channels; D007700:Kinetics; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism*; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins; D010100:Oxygen / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D011522:Protons; D051381:Rats; D013564:Sympathetic Nervous System / Q000502:physiology*; D013696:Temperature; D014475:Uncoupling Agents / Q000378:metabolism; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D007473:Ion Channels; D008563:Membrane Lipids; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010743:Phospholipids; D011522:Protons; D014475:Uncoupling Agents; D000071256:Uncoupling Protein 1; D006153:Guanosine Diphosphate; D010100:Oxygen