A New Study Discloses The Biology Of The Hunger Hormone, Leptin

In a new study, Yale researchers offer information on leptin, a hormone that plays a key role in appetite, overfeeding and obesity. They said their findings improve knowledge about leptin and weight gain, and also have a potential strategy for developing future treatments to lose weight.
The study, led by researchers at Yale and Harvard, was published in the week of June 17, 2019, in the Proceedings of the National Academy of Sciences.
Leptin, which is secreted by fat cells, tells about the brain when it is stored in body fat and in the liver is depleting. It has not been well understood how low plasma leptin, the largest component of the blood, increases appetite. Researchers will study the biology of leptin in rodents. The influence of nerve cells in the brain known as AgRP neurons, which regulate eating behavior, was also investigated.
The researchers found that the mechanisms by which reductions in plasma leptin stimulate food intake are not limited to the brain, as previously stated. In rodents, fasting first activates the leptin receptors in the brain, followed by an intermediate step involving the endocrine system. This system includes the pituitary and adrenal glands, the secretion of another hormone, corticosterone, and the regulation of energy, the responses to stress and the intake of food.
The research team discovered that this chain of events is necessary for leptin to stimulate hunger when food is restricted, or when diabetes is poorly controlled and leptin plasma falls below a critical threshold Medicine in the School of Medicine Yale, and co-author of the study.
Shulman noted that the researchers also showed that plasma corticosterone activates AgRP neurons, which increases hunger when leptin or blood sugar levels are low. In humans, leptin and blood sugar decrease when people die.
These findings add to the knowledge of the results on leptin, which has been the focus of research on obesity and weight loss since its discovery in the 1990s. The study reveals "the basic biology of leptin and how the endocrine system is mediating its effect for ingesting food under conditions of starvation and controlled diabetes, "said Shulman.
The research also supports a different strategy for the development of drugs to treat obesity. "It suggests that AgRP neurons may be an attractive therapeutic target," he said.
Other authors of the study are Rachel J. Perry, Jon M. Resch, Amelia M. Douglass, Joseph C. Madara, Aviva Rabin-Court, Hakan Kucukdereli, Chen Wu, Joongyu D. Song and Bradford B. Lowell.
This study was funded by grants from the Public Health Service of the United States.

By: Preeti Narula

Content: https://www.sciencedaily.com/releases/2019/06/190618113120.htm