Chronic alcohol intake induces the oxidative capacity of brown adipose tissue in the rat

The present study was carried out to elucidate the effect of long-term alcohol intake on the oxidative capacity of brown adipose tissue in the rat. Rats housed at room temperature were given water containing 10% ethanol for six months, while controls received water alone. Fully cold-acclimated rats (exposed to +4 degrees C for 6 weeks) served as the second control group. Alcohol did not alter the food intake of the rats compared with the controls kept at room temperature, but it did cause a mean decrease of 8 ml in fluid consumption. There was no difference in the increase in body weight between the groups housed at room temperature. Body weight of the rats exposed to cold did not change during cold acclimation. No morphological liver changes were observed in alcohol-fed rats, but some changes related to long-term alcohol consumption were found in the myocardium. Chronic alcohol intake increased the quantity of brown adipose tissue and its protein content but changes were not as great as in the cold-acclimated rats nor did alcohol increase protein content per unit of the adipose tissue as did cold. On the other hand, the specific activity of mitochondrial cytochrome oxidase increased by 90% and that of succinate dehydrogenase by 130% in alcohol-fed rats, whereas specific activities of these enzymes displayed little or no change in the cold-acclimated rats. Results suggest that chronic alcohol ingestion induces the oxidative capacity of the interscapular brown adipose tissue in the rat, increasing the mass of BAT and specific activities of mitochondrial enzymes.