Researchers at the University of Cologne found that leptin makes moderately hungry mice choose sex over food. The scientists’ results were published in the journal Cell Metabolism.
Leptin is a hormone involved in the feeling of satiety. If it affected the brain of hungry rodents, then they stopped any form of eating behavior. Instead, the hormone provoked social activity.
As part of the work, the team stimulated mouse neurons in the hypothalamus. They focused on neurons that are responsible for leptin and neurotensin, two hormones associated with hunger and thirst. The authors found that these neurons are also involved in controlling social behavior and helping mice balance their nutritional and social needs.
“We can prioritize one: either eating behavior or sexual behavior. Our brains must somehow figure out what our most pressing need is. Activation of leptin receptor neurons causes mice to prioritize social interaction despite acute hunger or thirst. This makes biological sense, one must be able to ignore hunger or thirst in order to be able to mate,” the authors explained.
To see how the mice’s priorities changed based on their level of hunger, the team compared the behavior of mice from different groups (the first group had unlimited access to food, the second did not eat all night, and the third did not eat for five days). The researchers then used light and chemical signals to selectively stimulate neurons, allowing them to observe changes in the mice’s behavior.
As it turned out, stimulation had little effect on the behavior of fed and starving rodents, but the priorities of mice from the second group changed: they approached food more slowly, ate less in general, and spent more time communicating with potential partners.
“Next, we would like to understand how the activity of these cells changes during obesity or the development of eating disorders,” the researchers concluded.