Serial Studies on the Metabolism of Human Adipose Tissue. II. Effects of Caloric Restriction and Refeeding on Lipogenesis, and the Uptake and Release of Free Fatty Acids in Obese and Nonobese Individuals *

Abstract

Several metabolic functions of adipose tissue were measured serially in obese and nonobese human subjects during the course of caloric restriction and refeeding. Samples of tissue were removed from the subcutaneous depot by a simple technique of needle aspiration. Caloric restriction was shown to depress fatty acid uptake and esterification, virtually abolish fatty acid synthesis, and enhance free fatty acid (FFA) release from adipose tissue. Refeeding was associated with relatively slow restoration of fatty acid synthesis and esterification toward normal levels. Intravenous administration of glucose and insulin to starved obese individuals effected prompt inhibition of FFA release, slight restoration of fatty acid uptake, and esterification but no change in fatty acid synthesis. During starvation and its rapid termination by glucose and insulin, variations, in the rate of FFA release from adipose tissue were accompanied by parallel changes in the concentrations of plasma FFA.