The regulation of the endocrine system, responsible for the release of sex hormones in humans, could be affected by exposure to ultraviolet rays from the sun.
- A study has shown that sun exposure alters the regulation of the endocrine system.
- Exposure to the sun’s ultraviolet rays causes hormonal, physiological and behavioral changes.
- UVB rays increase testosterone levels.
The sun and the passion of love would be linked. Researchers from the University of Tel-Aviv (Israel) have discovered that exposure to ultraviolet rays from the sun plays a role in the regulation of the endocrine system, responsible for the release of sex hormones. They published the results of their study in the journal Cell Reports.
The role of the sun
The ultraviolet rays of the sun are known to increase testosterone levels in men and sunlight plays an important role in the hormonal but also behavioral regulation of sexuality. However, the mechanisms responsible for this regulation were unknown. This Israeli study helps to better understand them.
The effects of skin exposure to sunlight
The researchers exposed mice to UVB, solar rays whose wavelength is between 320 and 400 nanometers. The effects were significant, the females experienced a major increase in their hormone levels, enlarging the size of their ovaries and extending the breeding season. Increased attraction between males and females has likewise been observed, with both sexes being more willing to have sex.
In a second experiment, the study authors repeated the same process, this time removing a protective protein called p53 from the skin. This protein recognizes DNA damage and activates pigmentation when the skin is exposed to the sun. After exposing the mice to UVB, no changes were observed in their sexual behavior.
These results therefore led the researchers to believe that radiation exposure through the skin is responsible for the hormonal, physiological and behavioral changes that have been observed. The protective system is also responsible for regulating sexual behavior, they added.
Sunlight increases testosterone level
To confirm their findings in humans, the researchers asked 32 volunteers to complete a questionnaire on romantic passion behaviors for the first time. Then, a second time after being exposed to UVB in a medical center. The results showed an increase in romantic passion, and the men also noticed higher aggressiveness.
The study authors noted that they found similar results when they asked participants to avoid the sun for two days and then tan for about 25 minutes. Blood tests showed that exposure to the sun resulted in an increased release of hormones such as testosterone compared to the day before exposure.
On the other hand, data from the Israeli Health Services indicated that men experience higher levels of testosterone during the summer months.
