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The mechanisms outlined above do sound complex. Indeed, their complexity is one of the reasons they were discovered only recently. But their understanding allows scientists to have a clear view of the processes taking place in our body. Even more importantly, understanding of these processes should help to develop effective methods of preventing and treating obesity.
Regulation of hunger hormone production in the body
The major factor which controls ghrelin secretion is food that we eat. During fasting, ghrelin levels increase in blood. They fall back to normal after food is taken.
This was proven in animal studies. The effects of glucose on ghrelin secretion have also been studied. When energy stores in body are low, ghrelin stimulates glucose production and storage.
Studies have shown that ghrelin stimulates gastrin and insulin secretion. Both of these compounds are secreted in response to the increased glucose level in blood. So ghrelin secretion occurs in both situations of increased and decreased blood sugar levels.
There is a clear relation between the hunger hormone production and obesity
Ghrelin has become the main target of research in the treatment and prevention of obesity. Ghrelin plays a major role in the growth hormone secretion and regulation of appetite.
Studies have also shown that in the obese individuals, the level of growth hormone reduces resulting in low metabolic rate or lesser burning of calories. Clinical evidence shows an inverse relation between body weight and levels of both ghrelin and growth hormone. Administration of ghrelin in these obese individuals resulted in an increased levels of growth hormone and metabolic rate. This study has provided a possible method of treatment by altering growth hormone levels in obese individuals.
Ghrelin secretion responds differently to different types of food intake in obese people. Recent findings indicate that the hormone responsible for signalling satiety called ‘peptide YY’ rises less in obese in comparison to normal weight individuals. It was suggested that the hunger and satiety signals do not function normally in obesity.
Type II diabetes is seen commonly in patients with morbid obesity. They have insulin resistance, insulin deficiency and increased blood sugar levels. A study has shown lower levels of ghrelin in these individuals which may be the reason for development of type II diabetes.
On-going research has shown that ghrelin may be only one of the hormones responsible for controlling appetite and food consumption. More research is needed to understand the complex interactions involved in food intake and energy expenditure signals in the body. The biochemical mechanisms here are complex, but their full understanding will be valuable for developing the new medical approaches for treating obesity.