Testicles, the second brain of men? This question does not seem so absurd, according to the results of a study jointly conducted by Portuguese and English researchers. Published on 2 June in the magazine Royal Society Open Biology, this shows that the two organs have more in common than we can imagine. Notably, they share many genetic and functional similarities. This link explains, for example, why testosterone levels, mainly produced by the testes, affect character.

many genes and proteins

Researchers from the University of Aveiro in Portugal and the University of Birmingham in the UK compared proteins in cells from 33 types of tissue from organs such as the heart, intestines, ovaries and placenta. This analysis revealed that the testis and brain have 13,442 proteins in common. “The brain and testis have the most protein in common compared to other organs”, say the researchers. The study also found that both genes have the most common genes in all organs.

The similarities between the two bodies do not end here. Actually, the brain and the testes are the two big consumers of energy. The first is to carry out complex processes like thinking and secondly to produce millions of sperms per day. They both also have specialized cells that allow them to support neurons for the brain and germ cells for the testis.

result of development

Aside from their structure, the brain and testis are not more likely to function the same way. This can be seen in the behavior of neurons and testicular cells. Both cell types perform exocytosis, the process of secreting biomolecules from the cell into its external environment. This mechanism allows brain cells to communicate with each other through neurotransmitters. In sperm, this is the process that is used to merge with the egg and fertilize it.

According to the researchers, these similarities are due to their involvement in species, the evolutionary event that resulted in species differentiation. It is by this phenomenon that humans have managed to differentiate themselves from other animals, such as chimpanzees. It is specifically related to 60 genes that “Contribute to the definition of phenotypic character specific to humans as enhanced cognitive abilities”, indicate the authors of the study.