Human leptin is a protein of 167 amino acids that plays a key role in regulating energy intake and energy expenditure, including the regulation (decrease) of appetite and (increase) of metabolism. Leptin is produced by adipose tissue and the level of circulating leptin is directly proportional to the total amount of fat in the body. Once leptin has bound to the Ob-Rb receptor, it activates Stat3, which is phosphorylated and travels to the nucleus where it mediates gene expression. One of the main effects on gene expression is the down-regulation of the expression of endocannabinoids, responsible, among their many other functions, for increasing appetite. There are other intracellular pathways activated by leptin, but less is known about how they function in this system. Although leptin is a circulating signal that reduces appetite, in general, obese people who are resistant to the effects of leptin have an unusually high circulating concentration of leptin, in the same way that people with type 2 diabetes are resistant to the effects of insulin. Leptin is also found to stimulate endothelial cell proliferation and angiogenesis.
 
Detection Range:
    16 - 1000 pg/mL
Sensitivity:
    8 pg/mL