Adipose derived hormones

Adipose tissue is an important endocrine organ that secretes numerous protein hormones, including leptin, adiponectin, and resistin. These hormones generally influence energy metabolism, which is of great interest to the understanding and treatment of type 2 diabetes and obesity.

Their relative roles in modifying appetite, insulin resistance and atherosclerosis are the subjects of intense research, as they may be modifiable causes of morbidity in people with obesity.

History of adipose derived hormones
It had been shown that adipose tissue secreted some unknown factor that influenced appetite. However, the importance of adipose tissue as an endocrine organ was only fully appreciated in 1995 with the discovery of Leptin, the protein product of the Ob gene. Leptin is a strong appetite suppressant that, when deleted, causes early onset severe obesity in humans and in animal models. The discovery of leptin and its effects on appetite led to hopes of a treatment for obesity and type 2 diabetes, a major disease in the developed world. Unfortunately, clinical studies using leptin as a treatment for obesity in humans failed to show improvement, leading some scientists to conclude that the brain can become resistant to leptin, even at supra-physiological levels (the so-called "ceiling effect"), rendering treatment with leptin ineffective. However, as geneticists learn more from the few cases of leptin gene mutations, the possibility remains that, although leptin was ineffective at treating obesity across the population, some individual obese patients might still benefit from its use as an anti-obesity medication.

Research into the adipose-derived hormones adiponectin and resistin is ongoing. Like leptin, these hormones also affect energy balance and metabolism, and are therefore targets for new drug research.