New contraceptives for men

2008/07/05 Galarraga Aiestaran, Ana - Elhuyar Zientzia

• Anatomia/Fisiologia
• Osasuna
• Farmakologia

One of the most investigated is the pill. It is the contraceptive most used by women, and the goal is to get something like this for men. One of the ways for this is hormonal treatment, something similar to the female birth control pill, but with male hormones.

Testosterone is responsible for the sexual characteristics of men, such as the growth of beard or high muscle mass. In addition, it is directly related to the production of sperm. Testosterone gives the brain the signal that there is enough sperm.

In short, the sperm production cycle begins in the brain. A hormone secreted by the cerebral hypothalamus acts on the pituitary. The pituitary secretes then two other hormones that reach the testicles and stimulate the production of sperm.

With the formation of sperm, testosterone is secreted by the testicles and another hormone, inhibine. Inhibine acts on the pituitary to prevent the secretion of hormones that favor the production of sperm, while testosterone acts similarly in the hypothalamus. Thus, the brain detects the formation of sperm and interrupts the production cycle of them. Then, when the levels of inhibine and testosterone decrease in the blood, the cycle restarts.

One way to avoid the production of sperm is, therefore, taking testosterone. If the level of testosterone is constant in the blood, the brain does not flow hormones that give the signal to produce sperm, so in the testicles no sperm is produced. However, in the tests carried out by the researchers it has been observed that the presence of so much testosterone in the blood produces side effects such as acne, fattening, increasing the prostate.

They have also tried to combine testosterone with another hormone, progesterone, to avoid or at least reduce these side effects. This hormone is also used in female pills, which, like it breaks ovulation in women, prevents sperm formation in the testicles in men. Progesterone also has side effects as it influences the sexual characteristics of men. Therefore, progesterone should be taken along with testosterone.

Therefore, theoretically, the male pill should have testosterone and progesterone. But it could not be a pill: in digestion testosterone is divided, so there is not enough testosterone to reduce the side effects of progesterone. For all this, researchers are testing the combination of progesterone implants and testosterone injections.

Other options

Researchers are developing new contraceptives for men.

MCIP

This option is not at all equivalent to female pills. However, researchers have not yielded and, aside from hormone-based methods, they investigate other systems. For example, at the University of Massachusetts they have found a way to disable sperm from moving.

When sperm form, in the testicles, they have tail, but they are not able to move. This capacity is acquired by passing through tubes to which it gives a protein. Researchers are testing molecules that block this protein and are getting good results in animal experiments. So far, no side effects have been found, but they have to continue investigating.

At another university, Columbia, is being tested with another blocker. It seems to be based on a drug that was testing a pharmaceutical company. This medication caused faulty sperm and the pharmaceutical company abandoned the experiments. Now, researchers at Columbia University have studied the influence of a compound of this drug on the testicles and are testing whether it serves as a contraceptive. The results have been satisfactory in animals and expect to test it before time in men.

In addition to the pills, they are testing other methods. A reversible variant of vasectomy. In the vasectomy, some tubes are cut through which the sperm pass, while in this other method the tubes are blocked by introducing some silicone blocks that prevent the passage of the sperm.

Another striking and cheap method is based on the increase in the temperature of the testicles. The heating of the testicles prevents the formation of sperm. To achieve this, there are straps that support the testicles against the body. In addition, the time and temperature to which it is necessary to stay in the sauna is explained through some tables to avoid the production of sperm.

Opportunities are multiplying. However, research goes little by little and, although an effective and simple method is achieved, it will have to be seen if men use it.

Published in Gara