EFFECTS OF FASTING AND REFEEDING ON SOME METABOLIC CHARACTERISTICS OFRAT BROWN ADIPOSE-TISSUE

To investigate the effects of fasting and refeeding on rat interscapul ar brown adipose tissue (BAT), we determined in vitro oxygen consumpti on, in vitro lipolysis, DNA content and composition of fatty acid (FA) . Fasting decreased the weights of body and BAT, and the DNA content o f BAT. Fasting reduced both basal oxygen consumption and basal lipolys is of BAT. Fasting also suppressed the noradrenaline- and glucagon-ind uced increases in both oxygen consumption and lipolysis of BAT. In bot h triglyceride and phospholipid FA of BAT the extent of unsaturation w as increased by fasting. Refeeding restored all of these parameters to the control level. These observations indicate that fasting reduces b oth oxygen consumption and lipolysis of BAT, resulting in reduced ther mogenesis, while fasting could stimulate BAT in certain phases of its function as observed in FA composition.