The effect of age and cold acclimation on the metabolism of brown adipose tissue in cold-exposed rats

Abstract

The effect of exposure to cold (4°) on the incorporation of glucose carbon into total lipids of interscapular brown adipose tissue was studied in warm-acclimated and cold-acclimated rats of different ages. Exposure to cold had little effect on the very low incorporation in warm-acclimated rats regardless of their ages. Incorporation was always greater in cold-acclimated rats in the cold than in warm-acclimated rats in the cold, but the increase due to cold exposure was smaller in young cold-acclimated rats than in older cold-acclimated rats. The concentration of glucose in the blood was highest in the youngest rats and was increased further after exposure to cold; older rats did not become hyperglycemic in the cold. The relation between brown adipose tissue metabolism and nonshivering thermogenesis is discussed.