Raptin is a recently discovered human hormone produced by the

hypothalamus The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrin ...

during sleep. It is cleaved from reticulocalbin-2 (RCN2). Raptin binds to glutamate metabotropic receptor 3 (GRM3) in hypothalamus and stomach neurons that inhibit appetite and gastric emptying, respectively. A 2024 study reported that it signals satiety to the gut, curbing appetite. Poor/inadequate sleep reduces raptin levels, increasing appetite. Raptin levels measured lower in people with

obesity Obesity is a medical condition, considered by multiple organizations to be a disease, in which excess Adipose tissue, body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classifi ...

. Raptin levels peak during nighttime sleeping and decline during the day. A 2022 study reported that a lack of sleep increased

ghrelin Ghrelin (; or lenomorelin, INN) is a hormone primarily produced by enteroendocrine cells of the gastrointestinal tract, especially the stomach, and is often called a "hunger hormone" because it increases the drive to eat. Blood levels of ghrel ...

production, increasing appetite, and limits

leptin Leptin (from Ancient Greek, Greek λεπτός ''leptos'', "thin" or "light" or "small"), also known as obese protein, is a protein hormone predominantly made by adipocytes (cells of adipose tissue). Its primary role is likely to regulate long ...

, which disrupts satiety signals. A genetic study of 2,000 obese individuals led to the discovery of an RCN2 variant, which was present in a group of family members who suffered from Night Eating Syndrome (NES). The variant blocked raptin production, and all individuals with the variant were obese.

References

{{Reflist Hormones of the hypothalamus Experimental anti-obesity drugs