Secretin Hormone Secreted in Intestines Activates Brown Fat
Researchers at the University of Turku's PET Centre and the Technical University of Munich have collaboratively demonstrated a new manner of activating brown fat and producing a sense of fullness. The results have been published in the esteemed journal Cell.
Brown fat consumes energy, reduces the amount of harmful cholesterol and improves the body’s sugar levels. Stock photo.
In 2009, the scientific community was shaken by the finding that adults can have brown fat that activates in the cold and produces heat. Ever since the remedial physiological phenomenon was verified by imaging, scientists have been looking for new mechanisms of activation.
Earlier this year, PhD Mueez U Din demonstrated in his doctoral thesis – which was examined at the University of Turku – that also food activates the metabolism of brown fat. Eating a meal causes rapid change in various factors in the body, including hormone levels.
Secretin is a gastrointestinal hormone, secreted in the intestines in response to the passage of food. Some years ago, Professor Martin Klingenspor's research group at the Technical University of Munich discovered secretin receptors in the brown fat cells of mice and confirmed that secretin activates brown fat. Additionally, animals that received secretin were discovered to eat less. In these mice, the heat produced by brown fat served as a direct message to the brain, activating the production of pro-opiomelanocortin, which increases the sense of fullness.
Researchers are especially interested in how human brown fat is activated, and therefore two years ago Klingenspor contacted Turku PET Centre's metabolism researchers Professor Pirjo Nuutila and Academy Research Fellow, Docent Kirsi Virtanen. Together with them, Doctoral Candidate Sanna Laurila planned and carried out an imaging study on volunteer subjects.
– With FDG-PET imaging, we could demonstrate that intravenous reception of secretin also activates the glucose consumption in human brown fat. This means that secretin also increases brown fat metabolism in humans, says Nuutila.
Additionally, the study showed that the blood secretin concentration following a meal is connected to the activation of brown fat.
– A new finding in the study is the three-part chain of messaging between the stomach, brown fat, and the brain that can be a reason why brown fat is beneficial to metabolism, says Nuutila.
The research results have been published in the esteemed journal Cell, which is classified as a top Level 3 publication by the Finnish Publication Forum.
Li et al., Secretin-Activated Brown Fat Mediates Prandial Thermogenesis to Induce Satiation.
https://doi.org/10.1016/j.cell.2018.10.016
HK/MS