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.
The study will appear online in The Journal of Clinical Investigation.