Abstract
Brown adipose tissue (BAT) is a major site of enhanced nonshivering thermogenesis during cold acclimation. Cold acclimation is suggested to enhance BAT function through changes in its fatty acid (FA) compositions. Noradrenaline and glucagon have been shown to be involved in the regulation of BAT function. Subsequently, we studied the effects of chronic administration of noradrenaline and glucagon on FA compositions in triglyceride (TC) and phospholipid (PI.) fractions of rat interscapular BAT. 1. Both noradrenaline and glucagon suppressed the increase in the body weight, while increased the weight and DNA content of BAT. Noradrenaline decreased TG level (mg/100 mg) and content (mg/pad), and increased PL content but not its level. Glucagon increased TG content, but not its level. PL was not changed by glucagon. 2. FA in TG of BAT: Noradrenaline increased polyunsaturated FA (PU), while decreased monounsaturated FA (MU) . Glucagon increased saturated FA (SA), while decreased PU. 3. FA in PL of BAT: Noradrenaline increased PU, while decreased MU and arachidonate index. Glucagon did not influence FA compositions and all the indexes calculated in the present study. The results indicated that noradrenaline or glucagon could not thoroughly simulate the changes in FA compositions of BAT during cold acclimation, suggesting a participation of multiple factors in the changes in FA of BAT induced by cold acclimation.
