Perhaps, the first contraceptive for men

In terms of the variety of contraceptives, men are not so lucky as women: while women have a lot of hormonal drugs, the strong sex has to be content with condoms and vasectomy.

Of course, male sex hormones are described in detail; about what they do in the male body, it is well known. Therefore, potential methods of hormonal contraception for men have long been developed. But their clinical use is hindered by two reasons.

First, the effectiveness of such contraception for men is highly dependent on each specific case: literally the same dose of the same drug can work in one and not work for another. In addition, contraceptive hormonal drugs for men are usually directed against testosterone. As a result, in addition to protivotesterone drug, men have to take testosterone itself - to support muscle mass and libido. Finally, male hormonal contraceptives are fraught with side effects, and to take them into account is much more difficult than for women. (In women, the measure of drug safety is the ability to become pregnant and give birth to a healthy child, men do not have such "quality control.")

Therefore, many researchers working in this field are trying to find alternative non-hormonal methods of drug contraception for men. Not so long ago, researchers from the University of Edinburgh (Great Britain) suggested using the male infertility gene discovered by them: mutations in it inhibited the maturation of spermatozoa, and if you learned how to control this gene, it would give an effective contraceptive with a reversible effect. Scientists from the Baylor College of Medicine (USA), who published an article with the results of their experiments in the journal Cell, went along a similar path.

This time the BRDT protein was the object of research. It is synthesized only in the testes and carries in the molecule the so-called bromodomain. This domain allows proteins in which it exists to bind to modified amino acids in other proteins, histones. The latter, as we know, organize the packaging of DNA and determine which genes will be active and which ones will not. Consequently, those proteins that interact with histones have the ability to influence DNA activity and literally to decide the fate of the cell.

Researchers relied on the experiments of colleagues from Columbia University (USA), who showed that if BRDT cut this very bromodomain, it would slow the formation of mature spermatozoa in mice - just because of malfunctions in the packaging of DNA in sperm cell progenitor cells. The authors of the work decided not to interfere in the structure of the protein, not to mutate its gene, and instead synthesized the compound, which they called JQ1; this substance was bound to the BRDT protein, not allowing it to work. JQ1 was administered to male mice and within six weeks they measured the testis volume.

By the end of this period the testicle volume dropped by 60%, which indicated a strong decrease in the number of spermatozoa that formed in them. The number of spermatozoa really fell, and by 90%. In addition, the remaining spermatozoa were strongly impaired mobility. As a result, male mice became completely infertile. But at the same time, no hormonal changes were observed in them - and, it turns out, the rodent libido did not suffer.

Generally speaking, this drug can suppress the work of other similar proteins. However, according to the researchers, they did not observe any possible side effects in this connection. The huge advantage of JQ1, in addition, is that its impact is reversible: after some time after the termination of admission to the male fertility returned. The drug acts somewhere in the middle stages of the transformation of stem cells into mature spermatozoa, that is, the stem cells themselves remain intact. The researchers are going to check the substance they invented for longer-term side effects, and if everything goes well, then the male population may finally get an effective and safe contraceptive pill. Although, I think, its direct effect in the form of a "reduction in testicles" can scare off not one potential user.

[1], [2]