Sertoli Cells in the Testis and Their Role in Spermatogenesis

In order to safeguard the reproductive capacity and survival of all living organisms in their life, both the production of sperm and steroid must take place within the testis. Male sperm generation depends heavily on the sertoli cells, which are sustentacular cells. The somatic cells known as sertoli cells are responsible for maintaining the germ cells during the spermatogenesis process. Therefore, the sertoli cells are essential for keeping a healthy sperm count in males. Examples of cell-specific products that sertoli cells synthesise and release include: Androgen binding protein (ABP), which are regulated by hormone secreting cells of testis -FSH, Testosterone. Leydig cell-produced steroids, and/or other elements released by them. A unique fact about sertoli cells is of having a distinct identity called a dark nucleolus, in comparison to other cells of the germinal epithelium. Sertoli cells and developing germ cells may communicate because several Sertoli cell proteins are secreted in a cycle at various times during the spermatogenic cycle.

Spermatogenesis Process

The process of producing male gametes or sperm inside the testes, the male reproductive organs, is referred to as spermatogenesis. Various phases of this process often take place in the testes' seminiferous tubules. The somatic cells of the testes known as sertoli cells are necessary for the development of the testes and spermatogenesis. By regulating the microenvironment within the seminiferous tubules, sertoli cells aid in the direct contact transition of germ cells to spermatozoa. By acting on the sertoli cells, hormone secreting cells of testis like FSH and testosterone control the process of spermatogenesis. While testosterone's action is essential for spermatogenesis, FSH actS on sertoli cells by assisting only in their slight increased number, which further helps to promote the spermatogenic output. Additionally, Leydig cells secrete androgens that work together with the hypothalamus, and the pituitary gland to carry out the entire spermatogenesis process in males.

Secretion of Sertoli Cells

The following are the substances that sertoli cells secrete:

• Anti-Müllerian hormone (AMH) - released in the early weeks of foetal life.

• Inhibin and Activin - are secreted after puberty and together they control the release of FSH.

• Androgen or Testosterone Binding Globulin - raises the level of testosterone in the seminiferous tubules, which mildly encourages spermatogenesis.

• Oestradiol- sertoli cells convert testosterone to 17 beta oestradiol for promoting the spermatogenesis.

• Testicular ceruloplasmin - a protein that resembles ceruloplasmin.

Difference Between Sertoli Cells and Leydig Cells

Two significant cell types can be found in the seminiferous tubules of the testes of the male reproductive system such as: leydig cells and sertoli cells. Both cells contribute effectively to the spermatogenesis process. The nutritive cells found inside seminiferous tubules are called as sertoli cells, from which the male sperm cells receive the nutrition. The location of leydig cells is in the interstitial regions outside of seminiferous tubules. FSH stimulates sertoli cells, while LH stimulates leydig cells. Hence, the hormone receptors for each cell are expressed. The table below describes the difference between leydig cells and sertoli cells:

What is the Function of Sertoli Cells?

Sertoli cells play two distinct functional roles. First, during foetal and early postnatal life, they take part in the formation and development of the testis. Second, they support and nurture germ cells during the spermatogenesis process in post-pubertal life. The main factor affecting the quantity of sperm produced each day and, accordingly, the size of the testis in adulthood represents the number of sertoli cells per testis. The blood-testis barrier, a structure that separates the ad luminal compartment of the seminiferous tubules from the interstitial blood compartment of the testis, is made up of the obstructing connections of sertoli cells. Sertoli cells regulate the flow of substances into and out of the testis' tubules, including hormones, nutrition, and other compounds.

Sertoli Cell Degenerative Disorders

According to the "testicular dysgenesis syndrome" concept, abnormalities in the foetal testis and sertoli cells may be significant risk factors for the development of testicular dysgenesis syndrome (TDS) in people. TDS can cause problems like testicular germ cell cancer and rarely poor sperm counts. Sertoli cells' inability to properly remove apoptotic germ cells causes chronic inflammation in the testis and increases autoimmune orchitis.

Clinical Significance

The epithelial sex cords of the growing gonads give rise to sertoli cells. The group of neoplasms known as sex cord-stromal tumours includes sertoli-leydig cell tumours. Both sertoli and leydig cells are produced by these tumours, which causes the testicles to secrete more testosterone.

Interesting Facts

It's interesting to note that sertoli cells play an essential part in the production of sperm and also engage in phagocytic activity to remove extra cytoplasm during spermatogenesis, which makes them gain the popular term "mother" or "nurse" cells.

Important Questions

1. What produces sertoli cells?

Ans: AMH (anti-Müllerian hormone), inhibin, activin, testosterone binding globulin, testicular ceruloplasmin, and transferrin are among the compounds known to be secreted by sertoli cells.

2. What are Leydig cells and Sertoli cells used for?

Ans: The leydig cells display functional luteinizing hormone (LH) receptors, while the sertoli cells express functional follicle-stimulating hormone (FSH) receptors.

Key Features

• The only somatic cells that make up the seminiferous epithelium and have growing germ cells are called sertoli cells.

• Sertoli cells not only create a necessary setting for spermatogenesis, but they also control other aspects of testicular immunology.

• Sertoli cells' phagocytic elimination of apoptotic cells and leftover bodies during spermatogenesis prevents the autoimmune reactions by getting rid of autoantigens.