Cold-induced expression of the VEGF gene in brown adipose tissue is independent of thermogenic oxygen consumption.
To examine whether cold-induced vascular endothelial growth factor (VEGF) gene expression in brown adipose tissue involved generation of hypoxic oxygen levels by thermogenic processes, we cold-exposed wild-type mice, as well as uncoupling protein-1 (UCP1)-ablated mice in which no thermogenesis in brown adipocytes can be induced. Cold exposure stimulated VEGF expression in both wild-type and UCP1-ablated mice. Unexpectedly, the effect was 3-fold higher in UCP1-ablated animals, whereas cultured brown adipocytes from both genotypes responded identically to norepinephrine stimulation. These results demonstrate that generation of low oxygen levels does not contribute to cold-induced VEGF expression in brown adipose tissue, but the results are consistent with an adrenergic regulation of expression.
Fredriksson
J Magnus
JM
The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Sweden. Magnus.Fredriksson@zoofys.su.se
Nikami
Hideki
H
Nedergaard
Jan
J
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000693:Anaerobiosis; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics; D003080:Cold Temperature; D005786:Gene Expression Regulation; D007473:Ion Channels; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008817:Mice, Mutant Strains; D024101:Mitochondrial Proteins; D009154:Mutation; D010101:Oxygen Consumption; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D022722:Thermogenesis / Q000235:genetics; D000071256:Uncoupling Protein 1; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; C000604372:Ucp1 protein, mouse; D000071256:Uncoupling Protein 1; D042461:Vascular Endothelial Growth Factor A