How hunger blocks fertility

A molecule that may play a key role in obesity, drug addiction, and depression also turns off the reproductive system in times of severe hunger, according to Yale scientists. In a report in September in the Proceedings of the National Academy of Sciences, the researchers identified the molecule as melanin-concentrating hormone (MCH), a peptide that is made by the hypothalamus.

“Brain neurons that make MCH are quiet most of the time, but when the body is in negative energy balance, MCH neurons become active and can shut down brain neurons that control reproduction,” said Meenakshi Alreja, Ph.D., senior author of the paper and associate professor of psychiatry and neurobiology.