Hormonal Control

Spermatogenesis’s hormonal control is different from species to species. This is not properly known in humans. There is the interaction between the pituitary gland, hypothalamus, and Leydig cells during puberty which starts the process of spermatogenesis. Testosterone and follicle-stimulating hormone (FSH) can also initiate spermatogenesis in the absence of the pituitary gland. Besides inducing gonadal testosterone production LH (luteinizing hormone) also have a small role in spermatogenesis. The formation of the blood-testis barrier and production of androgen binding protein (ABP) by Sertoli cells is stimulated by FSH. For the initiation and maintenance of spermatogenesis level of testosterone is very important to be maintained which is done by ABP. After the development of testes, only testosterone is required to maintain spermatogenesis. Moreover, FSH is required for the initiation of separation of testosterone in the testes. By obviating the apoptosis of type A spermatogonia, the production of spermatozoa can be increased along with the increased level of FSH. The level of FSH can be decreased by inhibin hormone. Suppression of proapoptotic signals supports the process of spermatogenesis with the help of gonadotropins and also promotes the survival of spermatogenic cells. Through hormonal production, Sertoli cells play their part in spermatogenesis. Hormones like inhibin and estradiol are produced by them. Along with the production of testosterone Leydig cells also produce estradiol. In animals, estrogen is an important hormone for spermatogenesis. Another hormone that is important for spermatogenesis is prolactin.

Spermatogenesis is the development of haploid spermatozoa from germ cells of testis in seminiferous tubules. In the basement membrane of the tubules, there are stem cells that divide mitotically to start the procedure of spermatogenesis. Spermatogenesis stem cells is another name for these stem cells. Type A and B are the two cells that are produced by the division of stem cells. One type of cell refills the stem cells i.e., type A and primary spermatocytes are formed by the differentiation of type B cells. The final product of spermatogenesis is the production of haploid spermatids which is obtained by meiotic II division of secondary spermatocytes and this secondary spermatocyte is formed by meiotic I division of primary spermatocyte. One primary spermatocyte gives rise to two secondary spermatocytes and these two secondary spermatocytes give rise to two spermatids each. Through the process of spermiogenesis, the spermatids are transformed into spermatozoa. 

Sperms are basically adult spermatozoa. So, four haploid spermatozoa are produced by a single primary spermatocyte. In most sexually reproducing organisms sperms are the mature male gametes. So, it can be said that oogenesis in females and spermatogenesis in males is the version of gametogenesis in them. In mammals, this process occurs in seminiferous tubules of male testes. Spermatogenesis is a very important process for sexual reproduction and this process occurs under some optimal conditions. These optimal conditions are important to be followed in order to complete this process with full efficiency. In the regulation of this process, there are some implications that are done like histone modifications and DNA methylation. With the increasing age decrease in quality and count of sperms in males can be seen. 

Usually, this process starts with the onset of puberty and endures till death. Lumen is the storage for mature spermatozoa. The starting point of this process is seminiferous tubules. Cells move along tubes until they get mature and reach the lumen. Specifically speaking the bottom part is where the process starts and from there cells move deeper inside tubes and flow in it until they get mature and reach the lumen where they are finally stored. In the tube, there are simultaneously many divisions going on. These stages can be seen after cutting a tube transversely. A spermatogenic wave is known when different maturation stages are seen at the same time.