Anorexic women have much higher levels of a mysterious molecule
suspected to affect appetite, researchers have shown for the first
time. The peptide, called CART, could be a candidate for new
appetite-altering drugs, they say.
Levels of CART were 50 per cent higher in blood samples from
anorexic women, compared with women without the eating disorder,
says Sarah Stanley, an endocrinologist at Imperial College London.
CART levels were also found to rise as the women's weight fell.
However, the function of CART in humans is not known. "And
because we know so little, it is difficult to know if CART is the
cause of the weight loss or the result," Stanley told New
Scientist.
The team, based at Imperial College and the Eating Disorders Unit
at London's Maudsley Hospital, will now proceed with experiments
giving CART to humans to see if it has a real effect on
appetite.
"Understanding the biology of anorexia nervosa is terribly
important and any chink of light that might be shed on it through
molecular research is certainly worth pursuing," says Stephen
O'Rahilly, an expert in the molecular mechanisms of obesity at the
Cambridge Institute for Medical Research, UK.
Up and down
CART is made in a variety of places in the human body including
the brain, pituitary and adrenal glands. Studies in rats have linked
the molecule to appetite. But CART both increases and reduces the
appetite in rats, depending on which part of the brain it is
injected into.
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In the latest research, the team measured CART levels in the
blood of anorexic women, anorexic women who were in the process of
regaining weight, and recovered anorexic women who had maintained a
normal body weight for a year. "We found a very, very strong
correlation between plasma CART and body mass index," Stanley
says.
Next, as well as giving CART to people, the team plans to examine
CART levels in obese patients and those who have lost their appetite
because they have a malignant disease. CART could also be a possible
target for obesity drugs if it proves to reduce appetite, says
Stanley.
"CART is definitely expressed in the appropriate parts of the
hypothalamus to be involved," O'Rahilly told New Scientist.
"But one should be cautious about leaping immediately to therapeutic
applications." For example, it is difficult to know if measurements
of CART in the blood reflect the situation in the brain, he
says.
The findings were presented at the British Endocrine Societies
annual meeting in Glasgow, UK. |