It has been known that there is a protein that floats in the blood called growth and differentiation factor 15 (GDF15) that seems to regulate body weight. Mice that have high levels of GDF15 show reduced food intake and body weight and do not develop obesity and insulin resistance like wild-type mice, whereas the converse is true in GDF15-deficient mice. In humans high blood levels of GDF15 correlate with decreased body mass index (BMI) in people with cancer, injuries, heart disease and chronic kidney disease. Because this system is activated in response to body damage and stress it is called the emergency pathway. It is mostly made in the liver in response to those stresses. The mechanism behind this signal have not been known because we hadn’t found the cell receptors for GDF15. Now 4 research groups have found those receptors in the brain. (1)
The receptor has been named glial-cell-line-derived neurotrophic factor receptor-a-like. (GFRAL) In experiments in mice and in mice bred to not have this GFRAL they have shown that this receptor is how GDF15 makes them stop eating when in turn it signals other parts of the brain.
The question I have is why does God make you stop eating when you have bad stress? There must be some kind of survival advantage. That might be related to the benefits of calorie restriction.
GDF15 receptor in hand, treatments for obesity might happen. Also weight loss from stress might be treatable – if it is really bad in the case of stress – it might be a good thing as we mentioned.
Someday one of these magic bullets that keep being discovered is really going to work.
John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- email@example.com or phone-354-6605.