Introduction:
Ghrelin is a hormone that is produced in the stomach. This hormone is responsible for creating hunger. It is also called the hunger hormone. This hormone regulates the eating process. Hence, it is responsible for weight gain. Ghrelin blockers act against the action of ghrelin and help with weight loss.
What Is Ghrelin?
Ghrelin is a hormone released from the cells of the stomach. These were first identified in 1999. These travel to the brain. The brain reacts with the hypothalamus (eating center) and pleasure center to stimulate hunger.
It is also called the ‘go’ hormone, which directs when to eat. Obesity and weight loss are very difficult to manage. Since obesity is related to eating, this hormone may be targeted to control obesity. Its levels keep fluctuating throughout the day.
Ghrelin act by :
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Stimulating the brain.
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Slowing the metabolism of the body.
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Reduce the burning of fat in the body.
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Increases the accumulation of fat tissue in the abdomen.
If ghrelin is given to an individual, he is expected to eat 30% more food than the individual not given ghrelin. Some studies have found that there are fewer ghrelin hormones present in obese individuals when compared to thin individuals. It is also observed that people with anorexia have increased ghrelin levels in their blood. Hence, it is understood that ghrelin levels are inversely related to calorie intake.
What Is Leptin?
Leptin is a hormone that stops or suppresses hunger. It is produced in the fat cell. It helps in the maintenance of body weight. It signals the brain to reduce apatite and helps burn more calories.
Many studies have found decreased leptin levels in those who have lost weight. This may, in turn, increase the appetite. Some studies have found an association between obesity and increased levels of leptin. These increased levels of leptin inactivate the receptors for leptin. Because of this action, there won’t be any elimination of excess fat. Although a higher concentration of leptin is present, the appetite suppression system does not work in this situation.
What Are Ghrelin Blockers?
These exhibit antagonistic actions to those of ghrelin hormones. Hence, it is thought to be used in losing weight. Many studies are being conducted on ghrelin blockers. A research institute in California has developed a ghrelin vaccine that can be used as an anti-obesity and helps reduce fat in animals.
In future days, there may be a medication called ghrelin blockers. Since it blocks the brain’s center that is responsible for pleasure, it may affect mood regulation as a side effect.
What Is the Mechanism of Action of Ghrelin and Ghrelin Blockers?
Obesity is a major condition causing health issues and increasing exponentially worldwide. The prevalence of obesity has doubled in 30 years. Life expectancy is also reduced due to obesity.
The fat in the body is regulated by energy homeostasis.
Energy homeostasis includes
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Energy intake.
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Energy spent.
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Energy storage.
Various organs are involved in the regulation of appetite control.
They are
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Adipose tissue.
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Cells that are present in the stomach and gut,
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Thyroid gland.
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Areas of the hypothalamus.
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Centers in the brainstem that are involved in appetite control.
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Some local acting and circulatory factors.
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Carbohydrates, proteins, and lipids.
Fat tissue comprises 1 billion cells forming an endocrine organ that communicates with other tissues by adipocyte-released secretagogues. Leptin and adiponectin are important for weight control. Leptin is secreted from adipose tissues. Fat activates leptin receptors in the hypothalamus's arcuate nucleus (ARC). This leptin sends a signal of fullness.
Adiponectin is released from adipocytes. This adiponectin decreases insulin resistance, improves pancreatic β cells, and increases their function. It acts in the brain and mediates weight loss. In obese people, their levels are reduced.
In the stomach and gut, cells produce fullness peptides like ghrelin, cholecystokinin (CCK), glucagon-like peptide (GLP-1), Oxyntomodulin, peptide YY ( PYY), pancreatic polypeptide (PP), and amylin in response to digestion and absorption processes.
Signals produced in the stomach and distal part of the gastrointestinal system are sent to the hindbrain and give information about the size of the meal, taste, and chemical content of the food.
Obesity Treatment:
Vaccines used in treating obesity act by either suppressing appetite-stimulating hormones or blocking the absorption of nutrients. A study on rats revealed inhibition of feeding and suppression of food intake when anti-ghrelin vaccination was given.
When ghrelin receptor antagonists were given to rats, they improved glucose tolerance, suppressed appetite, and caused weight loss.
When a GHS-R1a ( growth hormone secretagogue receptor type 1a, ghrelin receptor type 1a) antagonist was administered to rats, it showed improved glucose tolerance and increased insulin secretion. When this was given daily to obese rats, it helped reduce food intake and resulted in weight loss.
Another study showed that the ghrelin receptor antagonist, [ D-Lys( 3)] GHRP-6 decreases food intake among ovariectomized mice.
Antiobesity drugs act on the CNS. Among these, the GLP-1 receptor agonist affects the gastrointestinal tract and the brain.
5HT2C receptor agonists regulate the serotonin system, which regulates appetite.
It is helpful for weight loss.
Another group of drugs acts on the dopamine system. This also promotes weight loss by suppressing the appetite.
Another study stated that 33A (mAb), when given as an injection, blocked the effects of ghrelin.
Vaccines use ghrelin immunoconjugates to induce an autoimmune response to the ghrelin peptide.
Immunization against ghrelin led to anorexia. But the disadvantages of using adjuvants showed an inflammatory response.
The antighrelin vaccine was developed. This was found to be good to use along with diet and exercise for obesity treatment.
One more study showed that IgG anti-ghrelin autoantibodies increased the orexigenic effects of ghrelin. They also showed that microbial factors are involved in increasing ghrelin-reactive IgG production.
Conclusion:
Ghrelin is a hormone produced in the body and helps in stimulating the appetite. Ghrelin blockers suppress the appetite. Hence, many studies were conducted to learn about the treatment of obesity. Even today, many researchers are trying to determine the best obesity treatment. Hence, knowing about ghrelin, leptin, and ghrelin blockers and their actions is important. Knowing this helps to seek help from a healthcare provider early. Early diagnosis helps in getting effective treatment. This, in turn, helps achieve a good quality of life.
