Scientists shed new light on how hormone works in weight loss

Washington: Scientists have found the how the hormone, which is a popular target to develop weight-loss drugs, works in our body.

Researchers from UT Southwestern Medical Center tracked down fibroblast growth factor 21 (FGF21) hormone, and discovered that it acts directly on the brain, activating another hormone called corticotropin-releasing factor (CRF). CRF then stimulates the nervous system, activating brown adipose tissue, which generates body heat by burning fat.

Professor of Molecular Biology and Pharmacology Dr. Steven Kliewer said that FGF21 has been known for playing a role in weight loss and they had previously shown that the hormone could act directly on the brain in mice to influence functions like reproduction. In the new study they have shown that FGF21 also acts directly on the brain to regulate obesity.

Specifically, researchers found that the FGF21-CRF pathway activated a part of the nervous system that controlled various involuntary body functions, called the sympathetic nervous system, to signal to brown fat. Brown fat, often considered the "good" fat, actually burns energy by generating heat, called thermogenesis, to protect from the cold. Once brown fat receives a "weight loss" signal, the tissue burns fat.

The findings are important to ongoing efforts to understand obesity at a molecular level and thus better respond to the obesity epidemic.

The study is published in the journal Cell Metabolism.