Washington: Scientists have discovered a brain protein that plays a role in regulating body weight.
The protein, called RGS9 2, had been previously related to the involuntary, random and repetitive body movements that are side effects of drugs used to treat Parkinson’s disease and schizophrenia.
Abraham Kovoor, an assistant professor in the University of Rhode Island’s College of Pharmacy, found the new role of RGS9 2 while studying these side effects, which are called dyskinesia.
Kovoor and his collaborators found that humans with a gene variation that could reduce RGS9 2 levels had a significantly higher body mass index.
Similarly, when they examined a strain of mice in which the RGS9 2 gene was deleted, so that these mice do not make RGS9 2 protein, they found that these weighed more than the wild-type strain and the percentage of body fat was much greater.
Conversely, when RGS9-2 protein is over-expressed in rats, they found that the rats lost weight.
Because RGS9-2 is normally expressed in the brain’s striatum, a section of the brain involved in both motor control and reward responses, Kovoor and his fellow researchers thought that the weight gain could be a result of an increased reward response triggered during eating.
“You would expect more eating from the mice without RGS9-2 (because they were the ones that gained weight), but that was not the case,” Kovoor said.
“Studies with humans, rats and mice implicate RGS9-2 as a factor in regulating body weight. But we had to look at another factor other than feeding behaviour.
“Our research shows that the striatum, through RGS9-2, has a role in regulating body weight that is independent of the motivation, movement and reward responses.
“We have identified a new gene that likely regulates weight gain through metabolism,” Kovoor said.
The results of his study were published in the November issue of PloS One.