Neonatal ghrelin (gut-derived hormone) directly influences development in the part of the brain related to appetite and the regulation of metabolism. Our subconscious motivation to eat is powerfully and dynamically regulated by this hormone signals. The study by The Saban Research Institute of Children's Hospital Los Angeles suggests a link between maturation of the gut-brain axis and later susceptibility to obesity, diabetes and cardiovascular disease.
The body weight and energy balance are regulated by a sophisticated network of neural circuits, and at its center is a collection of neurons or nerve cells in the hypothalamus of the brain called the arcuate nucleus, which contains sets of neurons that are sensitive to peripheral signals, such as metabolic hormones. For example, when the stomach is empty, the gut secretes ghrelin that acts on the arcuate nucleus to initiate feeding. However, until lately, little was known about the importance of ghrelin on development of brain mechanisms regulating body weight and appetite.
Mice studies have enabled the researchers to identify the physiological and neurobiological importance of ghrelin during early life. Researchers blocked the hormone soon after birth, which resulted in more axonal projections in the arcuate nucleus and caused lifelong metabolic disturbances, including obesity and diabetes. In another experiment, they increased ghrelin levels during this key developmental period and found that it impaired the normal growth of arcuate projections and caused metabolic dysfunction.
Principal investigator of the study Dr. Sebastien G. Bouret said, "Our study underlines the importance of maintaining a healthy hormonal balance - including ghrelin - during early life, to ensure proper development of brain-feeding centers. The correct timing and amount of both hormones is necessary for normal development of neural circuits in the hypothalamus. A better understanding of the relationship between ghrelin levels early in life and the development of disorders such as Prader-Willi syndrome or childhood obesity will be crucial as we seek to develop interventional studies to treat and, hopefully, reverse symptoms of metabolic diseases."
The study will appear online in The Journal of Clinical Investigation.