Cold Acclimation and Oxygen Consumption in the Thymus.
From: School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland.
Biochimica et biophysica acta
- Publish Date: Nov 2006
- ISSN: 0006-3002
- Volume: 1757
- Issue: 11
- Pages: 1463-8
- Medium: Print
- Language: English
- Citation (JAMA): Brennan Clare M, Breen Eamon P, Porter Richard K, et al. Cold Acclimation and Oxygen Consumption in the Thymus.. Biochim. Biophys. Acta Nov 2006;1757:1463-8
Abstract
Mitochondrial uncoupling protein 1 is usually associated with brown adipose tissue but has recently been discovered in rat and mouse thymus. We wished to establish whether there was a thermogenic role for UCP 1 in thymus and thus examined the effect of 5 weeks cold-acclimation on rat thymus tissue abundance, thymocyte oxygen consumption, thymus mitochondrial abundance, uncoupling protein 1 expression and function. We found that thymocytes from cold-acclimated rats had oxygen consumption rates 8 times less than those from rats held at room temperature and that thymocytes from cold-acclimated rats or rats kept at room temperature were noradrenaline insensitive. In addition, we found that thymus tissue or mitochondrial abundance was not increased after cold-acclimation. However uncoupling protein 1 expression per unit mass of mitochondria was increased after cold-acclimation, as determined by immunoblotting (approximately 1.7-fold) and GDP binding (approximately 1.5-fold). Consistent with our protein expression data, we also observed an increased, state 4 (approximately 1.5-fold), GDP-inhibitable (approximately 1.3-fold) and palmitate activatable (approximately 1.6-fold) oxygen consumption rates in isolated thymus mitochondria. However, extrapolation of our data showed that cold-acclimation only increased the amount of UCP 1 per gram of thymus tissue approximately 1.2-fold. Taken together, we conclude that UCP 1 does not have a thermogenic role in thymus.
Mesh Headings (Keywords): Acclimatization, Animals, Entropy, Female, Guanosine Diphosphate, Ion Channels, Kinetics, Mitochondria, Mitochondrial Proteins, Oxygen Consumption, Phosphorylation, Rats, Rats, Wistar, Reactive Oxygen Species, Temperature, Thymus Gland
Check for Full Text / PubMed Unique Identifier (PMID): 17022934
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