Role of Sertoli Cells in spermatid nutrition: Sertoli are the pillars of a multistory building ? Who is the mother of immature sperms when sperms were in infancy or in childhood!! Which cells nourishes immature spermatids of a infant boy to his pubertal age ?? Who looked after those would-be-sperms?? Ans: Sertoli cells are mother cells, which feed the primitive stem cells starting from the level of spermatogonia. The cut section of seminiferous tubule shows the periphery of the tubule formed peritubular myoid cells. Resting on the inner lining of the myoid cells, there are sertoli cells (SC) connected to each other by tight junction. The SC extends from the basement membrane to the lumens.
At the level of the basement membrane they from tight junctions with one another, thus dividing the tubular epithelium into a basal outer compartment, which has a functional permeability barrier with no contact with systemic circulation. So, the spermatogonia and their further development into spermiogenesis occur in the avascular microenvironment. The metabolic support for these developing germ cells is given entirely by Sertoli cells. Sertoli cells possess receptor for FSH in their plasma membrane and receptors for androgens in their nuclei.
The functions of the Sertoli cells are:
1. To sustain the germ cells. They metabolize glucose into lactate and pyravate and synthesize transferring necessary for iron delivery to the germ cells.
2. Each Sertoli cell is in contact with about 47 germ cells to which they give physical support.
3. Sertoli cells produce specific proteins such as androgen binding proteins (ABP) and inhibin.
4. They maintain a blood testis barrier along with the ovoid cells and make a physical support for the germ cells. If the barrier
Is broken ,e,g. by infection or scrotal injury the inflammatory cells of the body get access to the germ cells and this can give room to formation of antisperm antibodies.
5. Sertoli cells form the principle site for receiving the follicle-stimulating hormone(FSH). ABP is synthesized and secreted into seminiferous tubules by Sertoli cells. The secretion of ABP binds the intratesticular androgens, which are retained in the testis for the purpose of spermatogenesis.
6. ABP is very similar to sex hormone binding globulin (SHBG) produced in the liver. The difference between SHBG and ABP is mainly in the carbohydrate content.
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