Do you still find yourself going for that extra piece
of chocolate fudge cake even though you are not feeling hungry? Well, that
might be due to the absence of a hormone in your brain which is making you eat
more just for the pleasure of it.
According to a new Rutgers Robert Wood Johnson Medical
School study published in Cell Reports
, it was found
that when the hormone called glucagon like peptide-1 (GLP-1) was reduced in the central nervous system of
laboratory mice, they overeat and ate more high-fat food.
mice in which the GLP-1 deficiency was induced ate beyond the need for calories
and showed an increase preference for high-fat food," said Vincent Mirabella, a medical
school and doctoral student who co-authored the study. Whereas when the GLP-1 signaling system in the brain
of the mice was enhanced, they were able to block the preferences of high-fat
Along with many other functions in the body, the GLP-1 peptides play a role in
regulating the body's eating behavior. These peptides are small sequences of
amino acids that are secreted from cells in both the small intestine and the
brain. They are supposed to let our brain know when we are satisfied and stop
It has still been unclear as to how the GLP-1 released in the brain contributes
to appetite regulation, said Rutgers scientists. But this is not the only
reason why people overeat, the study shows new evidence that targeting neurons
in the mesolimbic
dopamine system is a
better way to control overeating and obesity with lesser side effects than
targeting the whole body. The mesolimbic dopamine system, also known as reward pathway, plays a major role in
the neurobiology of addiction. This system is the most significant neural
pathway of the brain where changes occur in all known forms of addiction.
When the GLP-1 hormone is activated in the mesolimbic system, it hindered the
communication between neurons which interact to control reward behaviors,
including eating. The result of the study was that the mice consumed less food
altogether and importantly, lost the preference for high fat food.
are the same areas of the brain that controls other addictive behaviors like
drug and alcohol abuse and nicotine addiction," said senior author and assistant professor
Zhiping Pang. "We believe that our work has broad implications in
understanding how GLP-1 functions to influence motivational behaviors."
The central nervous system
controls the eating behaviors such as why we eat, how much we eat and when we
stop eating which enables the body to respond to its
environment. This is the
reason why it is necessary to understand the motivation behind 'hedonic
hunger', the drive to eat for pleasure instead to gain energy. The motivational
factors and physiological factors will provide a better understanding of modern
eating habits, such as why a dysfunction may occur and can provide insights on
more targeted therapies.
There are very limited effective therapies for treating obesity. A drug that was
recently approved by the US Food and Drug Administration is now being used as treatment for obesity
The drug mimics the GLP-1 hormone which was initially used to improve glucose
tolerance for those with type 2 diabetes
However this injectable medication that targets the whole body, can possibly
cause serious side effects including pancreatitis, gall bladder disease and
eating, which causes obesity, can be considered a food addiction, a
finding out how the central nervous system regulates food intake behavior via
GLP-1 signaling, we may be able to provide more targeted therapy with fewer
side effects," said Pang.