Key News in Family Medicine January 18, 2019 (6 of 7)

Recently discovered regulatory mechanism helps body control fat metabolism rate, according to new study published January 17, 2019 in open access journal PLOS Biology by Ligong Chen of Tsinghua University in Beijing and colleagues. The discovery can lead to new drugs to help burn stored fat and reduce weight.

Adipose tissues can be white, brown or beige and differ not only in color but also in metabolism. White fat is primarily a storage tissue, with a low rate of metabolism; Brown adipose tissue, on the other hand, is rich in mitochondria and burns stored fat, releasing heat to warm the body, a process called thermogenesis. After prolonged exposure to cold, brown-type fat cells develop into white fat, making it beige, and beige fat cells also burn fat to keep the body warm.

The noradrenaline hormone, a hormone that stimulates the surface effects of the cell, is then stimulated by thermogenesis and is then absorbed into the cell and degraded to avoid excessive stimulation. A mechanism of uptake of norepinephrine by fat cells has already been described, but its absorption rate is relatively low, suggesting that there might be another route.

In the new study, the authors found that beige fat cells in mice had high levels of protein called organic 3 cation transporter (Oct3), capable of importing norepinephrine into cells for its degradation. . The authors showed that reducing the level of byte 3, and thus slowing the degradation of norepinephrine, resulted in a higher rate of fat metabolism in beige fat and a higher body temperature. When exposed to prolonged cold, Oct3-deficient mice increase beige fat content more rapidly than their control controls, accompanied by increased activity of thermogenic and mitochondrial biogenic genes.

Fortunately, when they examined the databases on human genetic badociations, the authors found that the possession of versions of the OCT3 The gene that makes the OCT3 protein with a reduced transport function was badociated with a higher metabolic rate. Together, these results indicate that OCT3 plays an important role in regulating the rate of beige fat production and thermogenesis in mice and humans.

"Our finding that a reduction of OCT3 the activity can lead to more beige fat and increased thermogenesis[es] the importance of this carrier in the recycling of catecholamine in adipose tissue, "said Chen. "The development of specific OCT3 inhibitors would open up new therapeutic possibilities for metabolic diseases."