Post Date December, 03 2023
To understand the mechanism of male contraceptives, it is first necessary to understand the process of sperm production. The seminiferous tube wall in the testis is covered with 5-8 layers of cells, including supporting cells and spermatogenic cells, also known as spermatogenic epithelium. Sertoli cells are arranged on the basement membrane of the seminiferous tubules, with the tip extending into the lumen. They have the functions of supporting, nourishing, and protecting spermatogenic cells at all levels, and may also have the function of regulating interstitial cells; The spermatogenic cells continuously proliferate and differentiate, starting from spermatogonia, primary spermatocytes, secondary spermatocytes, and sperm cells, and finally forming sperm, which are arranged layer by layer from the bottom of the base to the lumen. Each primary spermatocyte can divide into four sperm cells, which attach to the pits at the top of the supporting cells to obtain nutrients and undergo a process of metamorphosis and maturation to develop into sperm. Spermatogenesis is a continuous process, like an endless relay race, in which sperm is produced at all times, and the number of sperm formed each day can reach hundreds of millions. The well-developed sperm enters the epididymis with testicular fluid. The spermatogenesis process is mainly involved and regulated by hypothalamic, pituitary, and gonadal hormones.
Male contraceptives can work in the following different ways:
(1) The long-term use of large amounts of gonadotropin releasing hormone inhibits spermatogenesis by reducing the secretion of pituitary gonadotropins (follicle stimulating hormone and luteinizing hormone) through mediation.
(2) Use the corresponding antibodies to follicle stimulating hormone and luteinizing hormone to block the action of this hormone. However, due to the fact that both hormones contain the same subunit a and are the same as the subunit a of thyrotropin, when the antibody cannot specifically counter this hormone, it may cause unnecessary side effects.
(3) The use of autologous hormones, such as testosterone alone or in combination with progesterone, inhibits the secretion of gonadotropins by the pituitary gland and inhibits spermatogenesis through negative feedback. Testosterone heptanoate can be injected regularly to achieve an anti fertility effect that can be restored after withdrawal, making it a promising male contraceptive. The above drugs interfere with the spermatogenesis process by inhibiting the hypothalamic pituitary gonadal axis. Drugs are expensive and inconvenient to use, and they also inhibit the function of testicular interstitial cells, resulting in a decrease in testosterone levels, decreased libido, or sexual dysfunction. Therefore, further research is still needed to address this issue. Although testosterone also inhibits the function of mesenchymal cells, it does not affect sexual function due to its substitutive effect, and has a good application prospect.
(4) Gossypol, a drug that selectively inhibits spermatogenic epithelium, was first discovered by Chinese scholars to have an anti fertility effect, and has been extensively studied and clinically tested in China. The study has attracted international attention. It is a male oral contraceptive that is inexpensive and easy to use, but also has certain side effects. No matter which male contraceptive pill has a similar disadvantage, that is, slow onset, which is due to the fact that the aforementioned drugs have no killing effect on the generated sperm; Moreover, because the spermatogenesis process requires a certain amount of time, the recovery of reproductive function is also slow after drug withdrawal.
