Physicians examine why men and women increase in different ways
When male and female mice consume the same high-fat diet, males gain significantly more weight than females. Physicians were now trying to figure out the reasons for this difference in weight gain between the sexes.
The researchers at the Texas Children’s Hospital examined in their recent study why there is a difference in weight gain between the sexes. The results of the research were published in the English-language journal ” Nature Communications ” released.
New mechanism discovered
One of the research goals was to better understand the role that the brain plays in controlling body weight, explains study author Professor Dr. Ing. Yong Xu from Baylor College of Medicine. The study identified a new mechanism that could contribute to this difference between the sexes.
These hormones play an important role
Two main factors are likely to be involved in the gender differences in body weight control: the sex chromosome and the sex hormones , explain the researchers. Men have both an X and a Y chromosome, and women have two X chromosomes, but scientists have little understanding of which genes contribute to the differences in weight gain. The most important sex hormone in men is testosterone, while women have more estrogen and progesterone in their blood. Scientists agree that these hormones are likely to play a major role in regulating body weight.
Mechanisms need to be better understood
Differences in sex chromosomes and in sex hormones are important factors, but it has always been questionable whether there is a third group of factors that also contribute to gender differences in the regulation of body weight, says Professor Xu. The current study is one of the first studies that the brain In order to understand weight control differences between men and women, the expert adds. Previous research has already shown that the brain has multiple neuron populations that are very important for weight control. In the current study, Professor Xu and his colleagues now determined whether these populations differ between male and female mice.
What function do neurons have?
One of the most important functions of all neurons is the firing of electrical signals. This is how neurons communicate with each other and with other tissues, explains Professor Xu. The experts compared the pulse rate of many types of neurons in males and females in their study. The physicians found some neurons, which fired their signals differently. In particular, scientists focused on a type called POMC neurons, located in the hypothalamus.
What are POMC neurons?
The so-called hyperthalamic POMC neurons help maintain normal body weight by inhibiting appetite and promoting energy expenditure in response to a high fat diet, the researchers explain. The pulse rate of POMC neurons was examined by electrophysiological techniques. The results show that female POMC neurons fire faster than male neurons, the researchers say. One of the genes tested, TAp63, is more expressed in women than in males.
What happens when Tap63 is deactivated
It is already known from previous research that when the gene TAp63 is turned off in the whole body of a mouse, the animal thereby becomes obesity ill, explains Professor Xu. In the current study, the gene was switched off only in POMC neurons and it was striking that this change had no effect on male mice. On the other hand, female mice thereby developed a male obesity , Switching off TAp63 not only influenced weight control in women, it also lowers the pulse rate of female POMC neurons to the level of the male neurons. Suppressing TAp63 in men, however, had no effect on the rate of firing of their POMC neurons, the experts explain.
New treatment strategies for obesity?
These findings led researchers to propose a novel mechanism that could contribute to gender differences in weight control. Female POMC neurons express higher TAp63 levels, which causes the neurons to fire faster than in men. This in turn means that females have less appetite, consume more energy and are therefore better protected from weight gain than males. The researchers believe that these results could facilitate the future development of gender-specific treatment strategies for obesity and associated metabolic disorders.
Further research is needed
The findings suggest that, in addition to studying chromosomal and hormonal differences between men and women, scientists should also be aware of this third category of factors, emphasizes Professor Xu. Further studies will hopefully further explore this research direction, the expert adds. (As)