Have you ever wondered why some people following a certain exercise program lose weight while others with the same weight and the same exercises do not?
After a related research, Japanese scientists concluded that the protein PGC-1-alpha (PGC-1-a), which is produced in the muscles during physical exercise, is responsible for this phenomenon.
This protein regulates the expression of genes involved in fatty acid oxidation and thermogenesis (the body’s metabolic process with the aim of producing heat), promoting the efficient consumption of energy in the muscles.
Ogawa Wataru, head of the study and a professor of endocrinology at Kobe University, and the team embarked on a study (“Adaptive gene expression of alternative splicing variants of PGC-1α regulates whole-body energy metabolism“) that aimed to understand the mechanisms by which exercise causes weight loss and why its effects vary among different individuals.
The ultimate goal of their research was the development of drugs that would enhance the effects of physical exercise.
“During our research we discovered two other forms of the PGC-1-alpha protein, PGC-1-ab, and PGC-1-ac, which have similar activity to the ‘alpha’ form. With one very important difference though.
With short-term physical exercise they increase in muscle 10 times more than ‘alpha’, which did not appear to increase. We therefore found that the “b” and “c” forms of the PGC-1-a protein are the regulators of energy metabolism in the body, especially during short-term physical exercise.
On the other hand, the PGC-1-a protein increases only with long-term systematic physical exercise (at least for six months) in which case it contributes to the development of muscle mass and fat burning.
With the absence of the “b” and “c” forms of the PGC-1-a protein, it means that the body is essentially “blind” to short-term physical exercise, consumes less oxygen and burns less fat,” notes the Japanese professor.
Experiments on rodents and humans
The researchers first performed experiments on mice and found that exercising the rodents significantly increased the ‘b’ and ‘c’ forms in their skeletal muscles. “By creating genetically modified mice lacking the ‘b’ and ‘c’ variants of the PGC-1-a protein, we discovered that energy consumption (energy expenditure) during exercise is suppressed.
Thus, while normal mice lose weight when they exercise, mice lacking the ‘b’ and ‘c’ protein do not lose weight as easily with short-duration exercise (15m/min for two hours). We also found that these mice gradually become obese even when they do not receive more than the recommended amount of food.”
The experiments were not limited to rodents. The researchers took muscle samples from people before and after exercise to investigate the degree to which PGC1-a protein and its variants increased, and looked at their energy expenditure during exercise.
“As in mice, the ‘b’ and ‘c’ forms of PGC-1-a protein were increased in human skeletal muscle by exercise, such as light jogging, but the extent of this increase varied between individuals. .
By comparing their energy expenditure during exercise with the degree of increase in the protein variants, we found that people with a lower increase in that protein also had a lower energy expenditure.”
These results suggest that the degree of increase in PGC-1-a/b/c protein is one of the factors that determine the efficiency of energy expenditure during physical exercise.
The role of nutrition and preparations
Today, anti-obesity pharmaceutical preparations are widely used throughout the world. However, these drugs are appetite suppressants, meaning they help with weight loss through dietary restrictions.
A drug that enhances the effects of PGC-1-a/b/c will, according to the Japanese professor, cause weight loss regardless of dietary restrictions, and the demand for such a drug is expected to be extremely high.
According to Ogawa Wataru, one of the drugs that increase PGC-1-a/b/c protein in skeletal muscle is clenbuterol, an active substance used to treat bronchial asthma.
The aim of the Japanese researchers is to search for substances that can safely increase the PGC-1-ab/c protein produced in the muscles by physical exercise. Kobe’s professor and his team are particularly focused on food and its ingredients because, they say, developing a drug takes time.
