This hormone controls how much you eat

New research published in the journal Nature Medicine suggests how a hormone called asprosin triggers hunger in the brain. The findings may help to treat obesity and overweightness.

Dr. Atul Chopra, a medical geneticist and assistant professor of molecular and human genetics and of molecular and cellular biology at Baylor College of Medicine in Houston, TX, is a corresponding author on the study.

Previous research led by Dr. Chopra discovered the hormone for the very first time. Researchers then found that the hormone is generated by fat, and that it regulates blood sugar levels by traveling to the liver and “telling it” to release glucose into the bloodstream.

And now, Dr. Chopra and his colleagues have shown that the hormone also affects the brain’s hypothalamus, regulating appetite and weight.
Studying asprosin and appetite

When the hormone was first discovered in 2016, Dr. Chopra analyzed only two patients with a very rare genetic disorder called neonatal progeroid syndrome (NPS). One of the symptoms of the disease is extreme leanness, as the body is unable to accumulate fat.

The researchers were able to identify a genetic mutation in NPS that is responsible for a deficiency in asprosin.
“Compared with individuals with normal weight, [individuals with NPS have an] abnormally low appetite,” says Dr. Chopra. “Because these patients have low blood asprosin levels due to their mutations, we wondered whether asprosin was, in fact, necessary to maintain normal appetite in people.”

To investigate this, the scientists genetically modified mice to have the NPS genetic mutation. As expected, this resulted in low blood levels of asprosin in the mice.

The rodents also showed NPS symptoms such as extreme thinness and low appetite.
How asprosin controls ‘hunger’ neurons

Then, Dr. Chopra and colleagues administered asprosin to the mice, in an attempt to see its impact on the animals’ appetite and study the brain circuits involved.

“[W]e were able to reverse the low appetite simply by administering asprosin to the mice,” explains Dr. Chopra. Significantly, the researchers also found that the hormone stimulates two types of neuron.