Ethanol-induced hypothermia and thermogenesis of brown adipose tissue in the rat.
The effects of two ethanol doses (2 and 3 g/kg) on colonic temperature and levels of norepinephrine (NE) and uncoupling protein (UCP) mRNA in the interscapular brown adipose tissue (IBAT) were examined in rats exposed to 20 degrees C or 4 degrees C for 2 h. The controls received 0.9% NaCl solution. Ethanol produced a significant hypothermic effect versus saline at both temperature conditions. The dose at 3 g/kg reduced colonic temperature more in the cold than at room temperature (p < 0.01), whereas the ambient temperature did not affect the decrease in rats that received ethanol 2 g/kg. At room temperature ethanol did not significantly change the levels of NE or UCP mRNA, whereas after cold exposure (4 degrees C) NE levels in the ethanol-treated rats were significantly lower than in the controls (p < 0.001). Ethanol did not prevent a cold-induced increase in the UCP mRNA levels, although it reduced an increase. The magnitude of the reduction in increase was dependent on the dose, being significant at the dose of 3 g/kg (p < 0.05). The results show that the ethanol-induced drop in body temperature is not necessarily related to IBAT thermogenesis, as indicated by the levels of NE and UCP mRNA.
Huttunen
P
P
Department of Forensic Medicine, University of Oulu, Finland. pirkko.huttunen@oulu.fi
Sämpi
M
M
Myllylä
R
R
D002001:Adipose Tissue, Brown / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001833:Body Temperature Regulation / Q000187:drug effects*; D002352:Carrier Proteins / Q000235:genetics; D000431:Ethanol / Q000494:pharmacology*; D007035:Hypothermia / Q000139:chemically induced*; D007473:Ion Channels; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D024101:Mitochondrial Proteins; D009638:Norepinephrine / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D000071256:Uncoupling Protein 1; D000431:Ethanol; D009638:Norepinephrine