Study shows how hunger-reducing hormone leptin and certain brain cells can help losing weight

Losing weight is not an easy task. It requires dedication, complex planning, research and expert advice at every step of the way. And even when one has  a weight loss plan, one  doesn’t know the exact specifics of how it aids in weight loss. Now researchers at Rockefeller University, US, have found that the nerve fibres that are present within the fat tissues can affect the ability of the body to burn stored fat.

Leptin: Hunger-inhibiting hormone

Leptin is a hormone which carries the signals between the fat deposits in the body and the brain. It allows the brain cells to curb appetite and boost energy expenditure, both of which help in regulating body weight.

The study

The researchers from the study, published in the journal Nature on 22 July, 2020, genetically engineered mice to stop producing leptin. This made the mice three times heavier than the normal mice as these mice started eating more and moving less. These engineered mice were not able to tolerate the cold because they could not control their body temperature as they could not properly utilise body fat to generate heat.

Then the scientists administered a dose of leptin in these mice. After getting the leptin hormone, these mice started eating less and were more active.

The most surprising fact was that after two weeks of having leptin administered, these mice started breaking down white fat (fat which contains unused calories) and the mice also regained their ability to use brown fat to generate heat.

The brain connection

The head of the study, Dr Paul Cohen from Rockefeller University, used an imaging technique and visualised the nerves inside the fat. The researchers determined the effects of leptin on these nerve cells present in the hypothalamus region of the brain. The scientists found that leptin regulated the agouti-related peptide and pro-opiomelanocortin (POMC) in the nerve cells of the hypothalamus.

Agouti-related peptide is a small protein-like molecule used by nerve cells that helps in stimulating the appetite and reduces the energy expenditure of the body.

POMC is a hormone present in the nerve cells of the hypothalamus and brainstem which helps in restricting food intake and increases the energy expenditure of the body.

Leptin manages the levels of both these molecules in the nerve cells of the brain. However, the scientists found that animals who lacked leptin or were leptin-resistant and obese also showed less fat deposition.

Fat reduction in people who do not respond to leptin

The scientists found that this agouti-related peptide and POMC in the nerve cells act with the help of brain-derived neurotrophic factor-expressing nerve cells present in the paraventricular nucleus of the hypothalamus (BDNFPVH).

Brain-derived neurotrophic factor (BDNF) is a regulator of energy balance which is found in the nerve cells present in paraventricular hypothalamus (PVH).

The scientists found that the depletion of the BDNF gene caused increased hunger, reduced locomotion (movement), reduced ability to maintain body temperature and severe obesity.

The scientists believe that by directly activating BDNFPVH, they will be able to treat obesity in people who do not respond to the leptin hormone.

For more information, read our article on 15 tried and tested tips to lose weight .

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