Effect of Fasting on Adipose Tissue Weight in Chicks, with Reference to Changes in Chemical Composition and Lipase Activity

The effect of fasting on adipose tissue weight was investigated in growing chicks. Fasting considerably decreased the wet weight of adipose tissue by decreasing the dry matter content per deoxyribonucleic acid. The decrease in dry matter content was mainly associated with the decrease in triglycerides, a major component in the adipose tissue. Both the activities of lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) were reduced markedly by fasting. An approximate 60% decrease in the plasma triglyceride concentration was induced by fasting. Fasting markedly decreased the incorporation of 14C-acetate into fatty acids and of 14C-palmitate into triglycerides in the liver in vivo and in vitro, whereas the 14CO2 expiration from [1-14C] palmitate in vivo and in vitro was increased by fasting. The mechanisms of triglyceride diminution in the adipose tissue of chicks by fasting is discussed.