Metabolism of Isolated Fat Cells

Abstract

A study was made of the effects of phospholipase C (Clostridium perfringens α toxin) and of insulin on lipolysis by fat cells isolated from epididymal adipose tissue of the rat. Both insulin and phospholipase C inhibited, in the absence of glucose in the incubation medium, the release of fatty acids and glycerol that was stimulated by submaximal concentrations of adrenocorticotropic hormone, epinephrine, glucagon, and theophylline. Both substances failed to inhibit the lipolytic action of high concentrations of adrenocorticotropic hormone and theophylline. The similar inhibitory action of phospholipase C and of insulin on lipolysis, an action that is independent of their stimulatory effects on glucose transport, provides additional evidence that both may be acting on a common parameter, possibly the plasma membrane, of the fat cell.