Contrary to the prevailing view, the hormone leptin, which is critical for normal food intake and metabolism, appears to regulate bone mass and suppress appetite by acting mainly through serotonin pathways in the brain, according to a recent study published in Cell by Yale School of Medicine researchers and colleagues at Columbia University. This new finding contradicts the view that leptin acts primarily in the hypothalamus.
"Our study challenges the view that the hypothalamus is the critical brain site where leptin acts directly to alter neuronal circuit function to suppress appetite and bone metabolism," said Yale researcher and study co-author Tamas Horvath. "We've now found a novel explanation for how leptin can act on the brain." Horvath is chair and professor of comparative medicine and professor of neurobiology and obstetrics & gynecology at Yale School of Medicine.
Food intake is influenced by signals that travel from the body to the brain. Leptin is one of the molecules that signal the brain to modulate food intake. It is produced in fat cells and informs the brain of the metabolic state. If animals are missing leptin, or the leptin receptor, they eat too much and become severely obese.
To determine whether leptin regulates bone mass through serotonin pathways, Horvath and his colleagues analyzed multiple lines of mice that were genetically altered to remove serotonin in the brain. "We found that when the serotonin pathway is turned off by leptin, the mice ate less, lost weight and their bones became weak. When the pathway is turned on, the mice ate more, gained weight and had more bone mass," said Horvath. "This might be why obese people tend to have much lower incidences of osteoporosis."
The study was designed by Gerard Karsenty of Columbia University as a follow-up to his groundbreaking work on the relationship between leptin and bone metabolism. Yale researchers provided a neurobiological framework fo
'/>"/>
| Contact: Karen N. Peart karen.peart@yale.edu 203-432-1326 Yale University Source:Eurekalert |
Related biology news :
1. Researchers identify proteins involved in new neurodegenerative syndrome
2. Texas researchers and educators head for Antarctica
3. MGH researchers describe new way to identify, evolve novel enzymes
4. University of Pennsylvania researchers develop formula to gauge risk of disease clusters
5. U of MN researchers discover noninvasive diagnostic tool for brain diseases
6. U of Minnesota researchers discover noninvasive diagnostic tool for brain diseases
7. Researchers discover new strategies for antibiotic resistance
8. Researchers find new taste in fruit flies: carbonated water
9. Binghamton University researchers investigate evolving malaria resistance
10. UIC researchers find promising new targets for antibiotics
11. Researchers develop simple method to create natural drug products
| Copyright © 2003-2012 Bio-Medicine. All rights reserved. ABOUT | CONTACT US | DISCLAIMER | PRIVACY POLICY | TERMS AND CONDITIONS |  |