Mouse Study finds Body Fat Affects Stress Response

New research suggests body fat appears to affect the way the brain deals with stress and metabolism.

University of Florida Health researchers discovered body fat sends a signal that may explain why stress causes a desire to eat more.

While the exact nature of those signals remains a mystery, researchers say simply knowing such a pathway exists and learning more about it could help break the vicious cycle.

Stress causes a desire to eat more, which can lead to obesity. And too much extra fat can impair the body’s ability to send a signal to the brain to shut off the stress response.

The findings are important and unique because they show that it’s not simply the brain that drives the way the body responds to stress, said James Herman, Ph.D., a co-author of the paper.

“It moved our understanding of stress control to include other parts of the body. Before this, everyone thought that the regulation of stress was mainly due to the brain. It’s not just in the brain.

This study suggests that stress regulation occurs on a much larger scale, including body systems controlling metabolism, such as fat,” Herman said.

The findings, which reveal a novel fat-to-brain feedback network, were published in a recent edition of the journal Psychoneuroendocrinology.

Researchers found that a glucocorticoid receptor in fat tissue can affect the way the brain controls stress and metabolism. Initially, such signals from the receptor can be lifesavers, directing the brain to regulate its energy balance and influencing stress responses in a beneficial way.

“The stress response in the short term is adaptive. It’s going to help you cope with stress,” Krause said. “The idea that fat is actually talking to the brain to dampen stress is new.”

Investigators also found that steroid hormones known as glucocorticoids activate their receptors within fat tissue in a way that affects a main component of the metabolic stress response.

Using mouse models, they found a unique connection between glucocorticoid signaling in fat tissue and the brain’s regulation of energy balance and stress response. Because glucocorticoid signaling is crucial to regulating the hypothalamic-pituitary-adrenal axis, fat tissue can directly affect central nervous system functions. These functions influence obesity, metabolic disease ,and stress-related problems, researchers concluded.

Understanding fat-to-brain signaling is a first step toward someday being able to influence the broad, complex relationship between stress, obesity, and metabolism.

Now that researchers have established that a fat-to-brain signaling pathway exists, a fuller understanding of how it functions could someday lead to drugs or other therapies that ward off the negative effects of long-term stress.

“The big question is the nature of that signal to the brain. We need to learn how to go in and break that cycle of stress, eating and weight gain,” Herman said.

Source: University of Florida