Gut Hormone FGF19 Shows Promise in Combating Obesity and Metabolic Disease
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A newly discovered link between a gut hormone and brain activity offers a potential breakthrough in the fight against obesity and related metabolic disorders. Research indicates that fibroblast growth factor 19 (FGF19), produced in the intestine, can signal the brain to increase energy expenditure, utilize stored fat, and improve metabolic health.
Metabolic Health
Scientists have long known about FGF19’s role in regulating bile acid production and glucose metabolism in the liver. Though, recent studies reveal a notable impact on the hypothalamus, a critical brain region responsible for coordinating energy balance. When FGF19 signals the hypothalamus, it activates thermogenic adipocytes – specialized fat cells that generate heat rather of storing calories.This process, known as thermogenesis, effectively boosts the body’s energy expenditure.
“FGF19 had already been linked to a reduction in food intake,” explains a senior researcher from the obesity and Comorbidities Research Center (OCRC) at the State University of Campinas (UNICAMP). “Our work broke new ground by showing that it also plays an critically important role by acting on the hypothalamus and stimulating an increase in energy expenditure in white and brown adipose tissue. Simply put, in addition to controlling appetite, it stimulates thermogenesis. So, in terms of therapy associated with obesity, it’d make a lot of sense.”
Mimicking Natural Processes: A New Approach to Drug Development
The research team believes FGF19 could inspire a new generation of medications for obesity, diabetes, and other metabolic conditions. The strategy involves developing compounds that mimic the action of naturally occurring substances in the body – a concept already demonstrated by drugs like Ozempic, which contains semaglutide and activates receptors mimicking the hormone GLP-1 to promote feelings of fullness.
Beyond appetite and fat storage, the study found that FGF19 also reduced peripheral inflammation and improved the animals’ tolerance to cold. Notably, these benefits disappeared when the sympathetic nervous system was blocked, highlighting its crucial role in mediating FGF19’s effects. Further experiments showed that exposure to cold increased the expression of FGF19 receptors in the hypothalamus, suggesting a coordinated response to maintain body temperature.
Global obesity Crisis Demands Innovative Solutions
The urgency for new treatments is underscored by the escalating global obesity crisis. The World Atlas of Obesity 2025 warns that current trends threaten to derail global health goals, including halting the rise in diabetes and obesity and reducing premature deaths from related diseases. Currently, more than 1 billion people worldwide live with obesity, a number projected to exceed 1.5 billion by 2030. Obesity is already linked to approximately 1.6 million premature deaths annually. In Brazil alone, around 31% of the population is considered obese, with 40-50% of adults failing to meet recommended physical activity levels.
Unraveling the Mechanisms of FGF19 action
The hormone FGF19 is primarily produced in the small intestine and plays a role in regulating bile acid production, glucose synthesis, and fat metabolism. Researchers at UNICAMP are investigating how to encourage the body to produce more FGF19 naturally. They are also working to understand the interplay between FGF19 and the neural circuits that govern eating behavior.
To pinpoint which brain cells respond to FGF19, the team analyzed data from over 50,000 single cells in the hypothalamus, identifying populations that express FGF19 receptors. This detailed analysis provides valuable insights into the hormone’s specific targets within the brain.
“The brain plays an extremely critically important role in controlling the body’s adiposity,” adds another researcher involved in the study. “At the same time as it receives data from peripheral tissues, it triggers commands.These commands, apparently using the sympathetic nervous system, seem to be an interesting way of thinking about energy expenditure.”
The research, published in the American Journal of Physiology – Endocrinology and Metabolism and highlighted as a Top Article in May, represents a significant step forward in understanding the complex interplay between the gut, brain, and metabolism. The findings offer a promising new avenue for developing effective therapies to combat the growing global burden of obesity and metabolic disease.