Gossypol: a contraceptive pill for men

　　sperm The generation process of

　　The wall of the seminiferous tubules in the testis is covered with 5 to 8 layers of cells, including supporting cells and spermatogenic cells, also known as seminiferous epithelium. Sertoli cells are arranged on the basement membrane of the seminiferous tubules, with their tops extending toward the lumen. They support, nourish, and protect spermatogenic cells at all levels, and may also have the function of regulating interstitial cells; spermatogenic cells continue to proliferate and differentiate, from spermatogonia, primary spermatocytes, secondary spermatocytes, sperm cells, and finally sperm cells, which are arranged layer by layer from the base to the lumen. Each primary spermatocyte can divide into four sperm cells, which attach to the pits at the top of supporting cells to obtain nutrients, undergo metamorphosis and mature process, and develop into sperm.

　　Spermatogenesis is a continuous process, like an endless relay race. Sperm is produced all the time, and hundreds of millions of sperm are formed every day. The fully developed sperm enter the epididymis along with the testicular fluid. The spermatogenesis process is mainly involved and regulated by the hypothalamus, pituitary gland and gonadal hormones.

　　male Oral contraceptives work in different ways:

　　1. Long-term and large-scale use of gonadotropin-releasing hormone can reduce the secretion of pituitary gonadotropins (follicle-stimulating hormone and luteinizing hormone) through downregulation and inhibit spermatogenesis.

　　2. Use corresponding antibodies against follicle-stimulating hormone and luteinizing hormone to block the effects of these hormones. However, since these two hormones contain the same a subunit, and are the same as the a subunit of thyroid stimulating hormone, when the role of the antibody cannot specifically fight against this hormone, it may cause unnecessary side effects.

　　3. Gossypol, a drug that selectively inhibits seminiferous epithelium, was the first to be discovered by Chinese scholars for its anti-fertility effect, and a large number of research and development efforts have been conducted domestically. clinical Trial. The research attracted international attention. It is a male oral contraceptive that is cheap and easy to use, but it also has certain side effects. No matter which type of male contraceptive pill is used, there are similar shortcomings, namely slow onset of effect. This is because the above-mentioned drugs have no killing effect on the produced sperm; and because the spermatogenesis process takes a certain amount of time, the recovery of fertility function is also slow after stopping the drug.

　　4. 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. Regular injections of testosterone enanthate can achieve anti-fertility effects that can be restored after the drug is stopped, making it a promising male contraceptive.

　　The above drugs all interfere with the spermatogenesis process by inhibiting the hypothalamic-pituitary-gonadal axis. The drug is expensive and inconvenient to use, and it also inhibits the function of Leydig cells in the testicles, resulting in a decrease in the level of cyclosterone and a decrease in sexual desire or sexual dysfunction , so further research is still needed to solve it. Among them, although testosterone also inhibits the function of Leydig cells, it does not affect sexual function due to its own replacement effect, and has good prospects for use.