Physiological role of a novel hormone FNDC5/irisin revealed in humans

October 1, 2012

A research team led by Dr. Christos Mantzoros, MD, PhD, at Beth Israel Deaconess Medical Center, Harvard Medical School, has published new findings elucidating the molecular and clinical role of FNDC5/irisin in humans.

Irisin is a recently identified hormone secreted from that has been found to serve as a providing key exercise-induced health benefits in mice. In these earlier studies, irisin showed direct effects on 'browning' of white fat which would lead to burning of excess calories. Discovery of irisin therefore raised expectations of potential for developing new therapies for .

In their study, Dr. Mantzoros and his team of researchers went one step further by uncovering the role of irisin in humans. They reported that whereas the cleaved soluble part of the FNDC5 molecule (irisin) is readily detectable in plasma, the uncleaved and unprocessed molecule FNDC5 is only rarely detectable.

They studied possible predictors of circulating irisin concentrations by performing cross-sectional and interventional studies in humans. They found that irisin levels reflect muscle mass primarily and are higher in younger male athletes than in older women. Also, muscle mRNA expression of FNDC5 was strongly and positively correlated with PGC1-α mRNA levels which confirms irisin as a myokine, a hormone secreted by muscle.

The Mantzoros group addressed the controversy of whether irisin levels change in humans during exercise by comparing levels in young healthy males who performed acute sprint runs and chronic sprint training for eight weeks. The results showed that irisin levels increase in response to acute exercise and irisin levels are closely and negatively associated with muscle ATP levels, pointing to a need for a prompt secretion of irisin after acute exercise to meet the needs for ATP and synthesis in muscle. Also reported were associations of irisin with , which increase muscle mass and metabolic outcomes in normal humans; a finding which will require confirmation by future studies.

Although this clinical study has revealed a significant amount of novel information regarding the physiological role of irisin in humans, much remains unknown regarding its function as a hormone and the regulation of FNDC5 synthesis and irisin secretion.

Explore further: Scientists isolate protein linking exercise to health benefits

More information: This article is "FNDC5 and irisin in humans: I. Predictors of circulating concentrations in serum and plasma and II. mRNA expression and circulating concentrations in response to weight loss and exercise" by Huh JY, Panagiotou G, Mougiosb V, et al. (DOI 10.1016/j.metabol.2012.09.002). The article will appear in Metabolism, Volume 61, Issue 12 (December, 2012), published by Elsevier.

Related Stories

Scientists isolate protein linking exercise to health benefits

January 11, 2012
A team led by researchers at Dana-Farber Cancer Institute has isolated a natural hormone from muscle cells that triggers some of the key health benefits of exercise. They say the protein, which serves as a chemical messenger, ...

Newly isolated 'beige fat' cells could help fight obesity

July 12, 2012
Scientists at Dana-Farber Cancer Institute have isolated a new type of energy-burning fat cell in adult humans which they say may have therapeutic potential for treating obesity.

Research debunks bodybuilding myth: Growth-promoting hormones don't stimulate strength

June 14, 2012
New research from scientists at McMaster University reveals exercise-related testosterone and growth hormone do not play an influential role in building muscle after weightlifting, despite conventional wisdom suggesting otherwise.

Exercise triggers stem cells in muscle

February 6, 2012
University of Illinois researchers determined that an adult stem cell present in muscle is responsive to exercise, a discovery that may provide a link between exercise and muscle health. The findings could lead to new therapeutic ...

Japanese researchers show that acupuncture can improve skeletal muscle atrophy

April 23, 2012
A team of Japanese researchers will reveal study results Monday at the Experimental Biology 2012 meeting that show how acupuncture therapy mitigates skeletal muscle loss and holds promise for those seeking improved mobility ...

Sprint to fight fat

June 29, 2012
Men can significantly cut the visceral fat in their abdomen with one hour of interval sprinting per week instead of relying on seven hours of jogging a week for a similar result, according to new Australian research.

Recommended for you

How rogue immune cells cross the blood-brain barrier to cause multiple sclerosis

November 21, 2017
Drug designers working on therapeutics against multiple sclerosis should focus on blocking two distinct ways rogue immune cells attack healthy neurons, according to a new study in the journal Cell Reports.

New simple test could help cystic fibrosis patients find best treatment

November 21, 2017
Several cutting-edge treatments have become available in recent years to correct the debilitating chronic lung congestion associated with cystic fibrosis. While the new drugs are life-changing for some patients, they do not ...

Researchers discover key signaling protein for muscle growth

November 20, 2017
Researchers at the University of Louisville have discovered the importance of a well-known protein, myeloid differentiation primary response gene 88 (MyD88), in the development and regeneration of muscles. Ashok Kumar, Ph.D., ...

New breast cell types discovered by multidisciplinary research team

November 20, 2017
A joint effort by breast cancer researchers and bioinformaticians has provided new insights into the molecular changes that drive breast development.

Brain cell advance brings hope for Creutzfeldt-Jakob disease

November 20, 2017
Scientists have developed a new system to study Creutzfeldt-Jakob disease in the laboratory, paving the way for research to find treatments for the fatal brain disorder.

Hibernating ground squirrels provide clues to new stroke treatments

November 17, 2017
In the fight against brain damage caused by stroke, researchers have turned to an unlikely source of inspiration: hibernating ground squirrels.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.