Now the fact that adipose tissue (lipids) is hormone dependent has become obvious. It produces several biologically active substances, simply – hormones, which are involved in the control of human eating behavior. But the main ones are two: leptin and ghrelin. They are antagonists of each other and are linked by a feedback loop. About them and you will learn from the article.
- Excess leptin
- Why lose weight?
- Appetite and hunger hormone
This hormone was discovered relatively recently, at the very end of the twentieth century. According to its structure, it is a polypeptide compound and is produced directly by adipocytes or fat cells, which are localized in the subcutaneous fatty tissue. Normally, it is a satiety hormone because its main function is to block the production and release in the hypothalamus of the center of hunger and minimize the synthesis of insulin, a pancreatic hormone. This is a reasonable physiological reaction of the body, since high concentrations of glucose activate the satiety center. The main points of application are selected hypothalamic neuropeptides.
The best known of these are:
- Neuropeptide Y, which generates feelings of hunger and activates insulin synthesis
- Thyrotropin-releasing hormone (TRH), which balances the thyroid gland.
- Corticotropin-releasing hormone (CRH) – controls adrenal function.
If an excessive amount of the hormone in the blood is a long-term process that accompanies obesity, leptin ceases to act as a satiety hormone. The explanation is simple: the hypothalamus develops habituation to the situation and, as a consequence, “leptin resistance” is formed. Therefore, the signals of sufficient filling of fat depots coming from lipocytes have no feedback. At the same time, insulin synthesis is blocked by leptin, which is regarded as a trigger for the development of type II diabetes. In “leptin resistance” energy expenditure is minimal, because the synthesis of thyroid hormones and heat exchange is reduced against the background of high production of glucocorticoids, which provokes suppression of reproduction.
Why lose weight?
Reducing total body weight is ambiguous about the concentration of leptin in the bloodstream and its regular effects on the body. But you have to understand that there is simply no other chance to normalize leptin metabolism besides weight loss. Especially paradoxical is the reaction of leptin to starvation. Therefore, first of all, those wishing to get rid of extra pounds should pay attention to increasing the energy expenditure, and reducing the caloric content of food should not fall below the maximum permissible physiological level.
Appetite and hunger hormone
This is the name of ghrelin, which was discovered a little later than leptin and belongs to the group of polypeptides. The hormone is synthesized mainly by the cells of the gastric mucosa. Ghrelin has two sides like any coin: on the one hand it is an appetite hormone and on the other it is a hunger hormone. Its level in the blood as an appetite hormone greatly increases the desire to eat aromatic and nicely served food. At the level of the underlying brain (hippocampus), leptin provides emotional, aesthetic pleasure when we eat. But, unfortunately, its high level not only enables one to enjoy food, but also provokes excessive consumption of food, even when one is already full. In other words, overeating.
As the hunger hormone ghrelin is synthesized on an empty stomach. Once there is nothing in the stomach, the body gives a signal to increase the level of ghrelin, and there is a desire to eat something. In order for the appetite not to become “wolfish,” the level of the hormone should not rise sharply. A relatively even concentration of ghrelin is guaranteed by frequent eating in mini portions, by keeping the stomach full, or the same role is played by one of the bariatric surgical techniques: the insertion of an intragastric balloon. More aggressive surgical techniques, such as sleeve gastric resection or biliopancreatic bypass, also lead to a drop in ghrelin, but, unlike intragastric ballooning, are not reversible.