Safer anti-obesity drug may be possible
DALLAS, July 19 (UPI) -- Boosting serotonin levels was the secret of the diet drug Fen-Phen's success, and this could be the basis of a safe substitute.
After Fen-Phen was taken off the market for causing heart complications in 1997, Joel Elmquist of University of Texas Southwestern's Medical Center's Center for Hypothalamic Research and a team of international researchers decided to find out why it controlled weight so well.
The active ingredients in Fen-Phen were fenfluramine and phentermine, and the team found that they increase levels of the brain chemical serotonin, which is best known as a regulator of emotions, mood, and sleep.
The researchers also discovered that serotonin activates neurons in the brain's hypothalamus that produce a hormone that stimulates melanocortin-4 receptors (MC4Rs). MC4Rs curb appetite. For a double whammy, serotonin also blocks NPY/AgRP neurons that produce a substance that blocks MC4Rs and stimulates the appetite.
"This finding increases the understanding of the molecular circuitry that controls body weight in response to changing levels of serotonin," Elmquist told the press. "An overarching goal of this understanding, for humans, is to design specific, safe drugs to fight obesity."
The study can be found in the July 20 issue of Neuron.
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