Obesity hormones

• Leptin Lowers appetite
• Ghrelin Gains appetite

Leptin

Leptin is thought to play a key role in the regulation of body weight. It is produced by adipose tissue and acts on satiety centres in the hypothalamus and decreases appetite. More adipose tissue (e.g. in obesity) results in high leptin levels.

Leptin stimulates the production of propiomelanocortin (POMC) in the arcuate nucleus. Alpha-melanocyte-stimulating hormone (alpha-MSH) is produced by cleavage of POMC and inhibits food intake.

?Leptin also stimulates corticotrophin-releasing hormone (CRH).

Low levels of leptin stimulates the release of neuropeptide Y (NPY), a potent appetite stimulant, in the arcuate nucleus of the hypothalamus. Conversely, high leptin levels inhibit NPY.

Ghrelin

Where as leptin induces satiety, ghrelin stimulates hunger. It is produced mainly by the P/D1 cells lining the fundus of the stomach and epsilon cells of the pancreas. Ghrelin levels increase before meals and decrease after meals