Seed fluid increases the likelihood of conception
Last reviewed: 16.10.2021
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In the seminal fluid found protein, which affects the female hormonal system, increasing the likelihood of conception.
In most animals, ovulation occurs on an internal schedule - the menstrual cycle. The egg ripens irrespective of the sexual activity of the female. The same thing happens with a person, and this allows (so that there are no more reliable contraceptives) to organize their own sex life in order to avoid pregnancy.
But in some animals (for example, in rabbits and camels), ovulation can be accelerated by sexual contact. For a long time it was believed that the signal here is the physical stimulation of the genital tract of the female during mating. However, in 1985, a hypothesis was advanced that the seminal fluid itself, without any physical stimulation, can accelerate the maturation of the egg. Several years ago, researchers from the University of Saskatchewan (Canada) tried to confirm this theory. They injected semen into the hind legs of the llama, and the llamas did start ovulating.
After that, scientists spent almost seven years trying to find in the seed a key molecule that acts on the hormonal system of females. They took samples of sperm llamas (which, like the closest relatives of camels, ovulate on the occasion of sexual intercourse) and bulls (in whose females ovulation does not seem to depend on such "external factors"). The spermatozoa were separated and the remaining liquid was fractionated in a variety of ways, including filtration, heat treatment, and digestive enzymes. After each attempt, the treated seminal fluid (more precisely, what was left of it) was administered to the females in order to understand whether the key molecule collapsed or not.
As a result, as the researchers write in the journal PNAS, they were waiting for an amazing result: instead of an unknown protein in the hands of scientists, there was a well-known nerve growth factor (NGF). In fact, NGF in bovine seed was discovered back in the early 1980s. But then no one knew what to do with this strange fact. Now it is more or less clear why the seed contains the protein necessary for the vital activity of neurons. According to the researchers, they were able to detect NGF in the semen of a variety of species: horses, rabbits, pigs, right up to humans. And the seminal fluid had an interspecies effect: with the help of the stallion seed, ovulation in llamas could be accelerated, and with the help of the lamb seed, ovulation in mice.
In some animals (for example, in cows that are ovulating according to the inner cycle), NGF did not accelerate ovulation. But in this case, it influenced the rate of formation of ovarian follicles and stimulated the development and functioning of the yellow body - that is, it influenced, even indirectly, the processes of the menstrual cycle.
In other words, the seminal fluid can really increase the probability of conception at the level of the female hormonal system. True, for this, the growth factor of the nerves needs to reach the higher parts of the nervous system and interact with the pituitary and hypothalamus, and the researchers have yet to find out the details of this journey. Well, the most intriguing question, which scientists are going to do in the near future: how this is the case with man? Can frequent sexual contacts reconfigure the female reproductive system for conception and should not we now evaluate the quality of male sperm even for such an indicator as the content of this "nervous" protein in it?
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