No male can resist superpheromones
Scientists at the University of Washington, working under the guidance of Dr. Timothy E. Holy, found a group of steroids in the urine of female mice, almost literally "hitting the head" of males. These compounds activate specialized nerve cells in the noses of potential partners with unprecedented efficiency.
The nerve cells studied by the authors belong to the additional olfactory (olfactory) system of the male nose. Humans and many humanoid monkeys, unlike other mammals and reptiles, do not have this system located in the so-called vomeronasal (coulter-nasal) organ. The additional and main olfactory systems recognize the particles contained in the air, but at the same time send signals to different regions of the brain. It is believed that the additional olfactory system is designed to register compounds whose sources are very close or in contact with the body, which determines its intermediate role between the registration of taste and olfactory sensations.
The identified steroids are glucocorticoid hormones involved in energy metabolism, the formation of stress reactions and the functioning of the immune system. Glucocorticoids control many important aspects of physiology and theoretically can provide detailed information about the health status of an animal.
It has long been known that urine, sweat and other biological fluids of animals (including humans) contain pheromones, which are chemical signals that can influence the behavior of other members of the population. Mammals use these signals for social purposes, such as marking territory, declaring their dominance, as well as when searching for a partner and mating. However, in most cases, the chemical composition of these compounds is unknown.
The authors identified a number of compounds that are exceptionally powerful stimulators of nerve cells of the nasal mucosa of mice. The detected pheromones activate nerve cells 30 times more strongly than all previously known urine pheromones of female mice combined. In addition, some of the new compounds selectively activate individual nerve cells. This means that the male brain can evaluate various aspects of the female's health through selective analysis of different pheromones.
Stress increases the amount of glucocorticoids in the urine of a female by 3 times, which indicates a direct relationship between the animal's health and glucocorticoid pheromones.
The pheromones identified by the authors are sulfated, i.e., before being excreted from the body, they were inactivated by attaching a sulfate residue. Enzymatic cleavage of the sulfate residue deprived the compounds of the ability to activate nerve cells. According to the authors, this fact is proof that the isolation of sulfated forms of these compounds is a mechanism that appeared in the course of evolution, designed for the exchange of information between representatives of different sexes.
The authors believe that glucocorticoid pheromones provide approximately 75% of the signals recorded by the additional olfactory system of males in the urine of females. The extraordinary effectiveness of the identified pheromones will facilitate both the study of the work of the additional olfactory system and the functions and role of pheromones.
Currently, the authors are studying changes in animal behavior under the influence of pheromones, and are also looking for additional pheromone signals recorded by an additional olfactory system of males in the urine of females.