[Pathophysiology of lipolysis in human adipose tissue (author's transl)]

Abstract

Lipolysis in human adipose tissue was measured as glycerol release in isolated fat cells and in adipose tissue homogenates. In isolated fat cells lipolysis proceeded optimally at pH 7.4, was stimulated 3.5 fold by noradrenaline and was not influenced by serum or protamine. In adipose tissue homogenates lipolysis was stimulated 4 fold by serum. Serum-stimulated lipolytic activity was optimal at pH 8.0, was inhibited by 1 M sodium chloride and protamine and was not influenced by noradrenaline. Lipolytic activity in isolated fat cells is ascribed on the basis of these observations mainly to the action of hormone-sensitive lipase. whereas lipolysis in adipose tissue homogenates in the presence of serum seems to be regulated by lipoprotein lipase. Thus, the lipolytic processes involved in the mobilization of triglycerides from adipose tissue and in the uptake or triglycerides into adipose tissue can be assessed separately, using the two described methods. The re-esterification of FFA, the second pathway in the mobilization of triglycerides, has also been investigated.