Adipose tissue is no longer considered solely as body fuel deposit but rather as an active participant of metabolic changes. Many specific receptors enable it to respond to different signals. As a source of numerous substances called adipokines the fat tissue constitutes an endocrine organ. The function of novel adipokines is progressively investigated and described. Leptine reflects total mass of body fat and interplays with hypothalamic satiety centers in regulation of feeding (its counter-partner is ghrelin of gastric origin) and to a lesser extent with the function of hypothalamopituitary- thyroid axis. Adiponectin and resistin are another pair of adipocyte hormones, which influence sensitivity/resistance to insulin in different tissues. Apelin and visfatin, most recently discovered adipokines, seem to modify insulin secretion and action.
Some differences are observed between visceral and subcutaneous adipose tissue secretory function as well as different liver effects. Changes in amounts of secreted adipokines are also induced by expansion or vanishing of the fat tissue. Adipokines should be analysed in relation to diabetes and metabolic syndrome, where obesity is an axial disorder. Besides, the adipose tissue is a place of steroids’ conversion and participates in precise regulation of local and general steroids’ balance. Adipose tissue was revealed a source of so called inflammatory cytokines (TNFα, IL-6, MCP-1) and factors affecting fibrinolysis and coagulation (PAI-1), despite lack of overt clinical signs of inflammation. They may play an important role in the pathogenesis of micro- and macrovascular complications, which are characteristic for metabolic syndrome and type 2 diabetes.