Brain Chemical Controls Appetite And Fat Storage

Scientists in Japan have identified the protein in the brain that controls appetite and body fat composition.

AsianScientist (Aug. 24, 2017) – Scientists from Hiroshima University have found a brain signaling molecule that can increase fat storage by the body, even on a regular diet. These findings, published in eLife, could pave the way for new treatments for obesity.

Over the course of evolutionary history, the body has favored the accumulation of fat as an essential store of energy for survival during times of famine. Unfortunately, in our modern age of extreme food abundance, overeating is a common occurrence, often leading to obesity. The molecular mechanisms by which the brain controls body fat content are still not fully understood.

In this study, a team of researchers led by Professor Kazuyoshi Ukena at Hiroshoma University initially observed that a protein known as neurosecretory protein GL (NPGL) was present in high concentrations in a specific part of the rat’s hypothalamus, a brain region that controls appetite and metabolism. This suggested that NPGL is involved in bodily energy regulation.

The researchers then carried out experiments on rats fed on two distinct diets for six weeks. One group of rats received a diet high in fat and sugar, while the other group was fed a regular diet. Both groups were then exposed to a virus that caused NPGL-secreting cells to increase their production of NPGL in the hypothalamus.

When NPGL was overproduced, rats that were fed on a high calorie diet exhibited a marked increase in their body mass and body fat composition. Interestingly, despite the overabundance of calories, the overall food intake of the rats also increased, indicating that appetite and feeding behavior had been elevated by NPGL. Although rats fed on a regular diet maintained their overall body mass and only moderately increased their food consumption, their body fat composition still increased, suggesting that NPGL specifically affects fat storage.

The scientists then performed the inverse experiment by depleting NGPL in rats using an antibody that inhibited NPGL synthesis. When NPGL levels were reduced, food intake and overall body mass remained unchanged, while body fat composition was lower even when rats were fed on a high calorie diet. These results further demonstrate that NPGL plays a critical role in regulating body fat composition.

Notably, NPGL levels were found to increase and decrease proportionally with blood insulin levels, suggesting that the NPGL system harmonizes with the body’s production of hormones that regulate blood sugar and energy storage. Taken together, these findings reveal an intricate neurochemical system where signals from the brain and other tissues combine to monitor the body’s energetic status and adjust feeding and metabolism accordingly.

The article can be found at: Iwakoshi-Ukena et al. (2017) Neurosecretory Protein GL Stimulates Food Intake, De Novo Lipogenesis, and Onset of Obesity.


Source: Hiroshima University.
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