III.2.B. The endocrine function of adipose tissue
In obesity, the increased energy intake leads to the accumulation of larger amounts of TG and adipose tissue. The TG are deposited in the cells, and the cells then divide.
The energy intake is regulated by the endocrine and the nervous systems.
The adipose tissue produces a number of hormones and/ or mediators (Table 1). An autocrine effect denotes self-stimulation, while paracrine regulation denotes that the producer cells exert effects on nearby cells. Hormones secreted by the adipose tissue are characterized by both regulatory mechanisms; furthermore, the adipose tissue, as an endocrine tissue, produces other molecules. Hormones secreted by the adipose tissue take part in both of the above-mentioned regulatory mechanisms, and they additionally have effects on the distant organs as an endocrine system.
|
Agents that affect the energy metabolism |
Factors that affect the development of adipose tissue |
|
Adiponectin |
Apelin |
|
Angiopoietin-like protein 4 (ANGPTL4) |
Transforming growth factor-β (TGF-β) |
|
Estrogen |
Proinflammatory/inflammation regulatory factors |
|
Androgen |
IL-1 receptor antagonist (IL-1RA) |
|
Insulin-like growth factor 1 (IGF-1) |
interleukin 6 (IL-6) |
|
Factors of the adipose tissue |
interleukin 8 (IL-8) |
|
Leptin |
interleukin 10 (IL-10) |
|
lipoprotein lipase (LPL) |
Monocyte chemoattractant protein-1 (MCP-1) |
|
Omentin |
Macrophage migration inhibitory factor (MIF) |
|
Resistin |
tumor necrosis factor-alpha (TNF-α) |
|
Retinol-binding protein 4 (RBP4) |
Renin-angiotensin system (RAS) |
|
Vaspin |
Angiotensinogen |
|
Visfatin |
Prostaglandins |
|
Complement-related factors |
|
|
acylation-stimulating protein (ASP) |
|
|
Adipsin complement factor B |
|
Table 1. Hormones secreted by the adipose tissue (hormones printed in italics will be discussed below)