1. Paper-Mammalian Reproductive Endocrinology and Toxicology-II
Paper code- MZE 401
Presented by-Suyash Garg
M.Sc. 4th semester
Department of Zoology
Indira Gandhi National Tribal University Amarkantak M.P.
3. Introduction
• Sertoli cells are named after Enrico Sertoli an Italian physiologist discovered
them while studying at the University of Pavia, Italy in 1865.
• He referred sertoli cell as ‘mother cell’ because they provide nourishment to
the developing sperm cell.
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• The Sertoli cells are also called Sustentacular cells or Sustentocytes or the Nurse
cell found in human testes. Extends from basal lamina of Semniferous tubule.
• They are the somatic cells of the testis that are essential for testis formation and
spermatogenesis. Sertoli cells facilitate the progression of germ cells.
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• Sertoli cells are specifically located in the convolutions of semniferous tubule,
as this is the only place where spermatozoa are produced.
• The most distictive feature of sertoli cell is that it has a dark Nucleolus.
• Testes are the male gonads and are oval in shape made up of 250 lobules.
• Each Testicular lobules contains 3-5 supercoiled semniferous tubule and each
semniferous tubules have 5-6 adjacent Sertoli cells.
7. Seminiferous tubules
• They are the basic unit of testicles, where spermatogonial stem cells (SScs) proliferates
and differentiates through cyclic events.
• These cyclic events includes mitosis, meiosis, post spermatid development, and
spermiogenesis (development of spermatids into mature spermatozoa) to generate
spermatozoa in process called Spermatogenesis.
• In human the semniferous tubules represent about 60%
of total testicular volume and they are about 200µm in diameter.
• The leydig cells are also present inside the testicles and are arranged at angular position of
semniferous tubules. 5
https://www.toppr.com/
Seminiferous Tubule
9. Leydig cells
• Leydig cells are the Endocrine part of testes and are arranged at angular positon of
Semniferous tubules.
• After the attainment of puberty the hypothalamic nuclei, the Arcuate nuclei through the
Kispeptin neurokinin B and Dynorphin (KNDy) nuron release GnRH in pulsatile
manner.
• Then through Hypothalamic–pituitary–gonadal (HPG) axis reaches to Adenohypophysis.
• Adenohypophysis contains Gonadotrope cell which have specific receptor for called
GnRH-R.
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10. • After binding with receptor gonadotrope cells release L.H. and F.S.H. into blood stream
through which these hormone reaches to target organ testes and target cell leydig and
sertoli cell.
• L.H. cause Testosterone biosynthesis then the Testosterone stimulate spermatogenesis
process by stimulating the sertoli cell.
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Testosterone stimulate spermatogenesis process.
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11. Book-Ashoke Kumar Boral
It is observed that hormonal effects of testosterone
on spermatogenesis are mediated through the sertoli
cells.
Testosterone enters the seminiferous tubule through
blood circulation. Within the sertoli cells testosterone
is bound to ABP.
This binding bring testosterone in close contact to
spermatozoa.
From the lumen of seminiferous tubule ABP transport
testosterone to the epididymis where they mature
and develope to the potential for fertilization.
Testosterone controlling Spermatogenesis
12. Secretory function of Sertoli cell
• Antimulerian Hormone (AMH) - Secreted during early stage of fetal life.
• Inhibins & Activins- Secreted after puberty works together to regulate F.S.H.
secretion.
• Androgen Binding Proteins (ABP)- Increase testosterone conc. in semniferous
tubule which stimulate spermatogenesis.
• Transferrin- is a blood plasma protein for Iron delivery.
• Ceruloplasmin- essential for normal movement of Iron from cell to plasma.
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13. Sertoli-Spermatids Interaction
• The Sertoli cells interacts or communicate with spermatids (germ cell, the spermatid is the haploid male
gamete that results from division of secondary spermatocytes) through the junctional complex which
is present between sertoli cells and these are involved in movement of germ cells.
• The cell junctions present in testes are -
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Tight Junction.
Adherens Junction.
Ectoplasmic Specializations.
Tubulobular Complex.
Desmosomes like Junction.
Hemidesmosome.
Gap Junctions.
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15. 1.Tight Junction
• Tight junctions are the example of occluding junctions.
• In the testis, the tight junction is an area of close contact between plasma membranes
of neighboring cells.
• Tight junction divides the Sertoli cell, forming a basal and an adluminal compartment.
Functions of occluding junctions.
Tight junctions have two main functions;
1) create a barrier, (Blood Testes Barrier), and 2) form a boundary.
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16. First, tight junctions create a semipermeable barrier, which restricts the passage of molecule,the
passage of molecules depends largely on their molecular weight and chemical nature.
Sertoli cells creates an Impermeable barrier called Blood Testes Barrier
Three main functions of the blood-testis barrier are
1) creates a specialized environment;
2) regulates the passage of molecules; and
3) serves as an immunological barrier
First, the blood-testis barrier contributes directly to the complex structural organization of the testis by
creating a specialized environment necessary for germ cell development and movement.
Tight junctions that constitute the blood-testis barrier also regulate the movement of products, such as
nutrients and wastes, both into and out of the seminiferous epithelium.
The third main function of the blood-testis barrier is to create an immunological barrier
Sertoli and germ cells maintain a unique antiviral defense system via the production of interferons
(IFNs), ILs, and cytokines.
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17. • The blood-testis barrier also prevents the entrance of Igs and lymphocytes into the
adluminal compartment
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Second, tight junctions in the testis form a boundary, dividing the Sertoli cell into basal
and an adluminal compartment.
bioscientifica.com
Tight junction
18. 2.Anchoring junctions.
• Anchoring junctions mechanically attach cells (and their cytoskeletons) to their
neighbors or to the extracellular matrix.
• Anchoring junctions function in signal transduction events because some of the
component proteins of these junctions are signal transducers.
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• Specifically, the ectoplasmic specialization is a modified
adherens junction type found only in the testis.
It uses actin filaments as its attachment site.
3.Ectoplasmic Specialization
• The ectoplasmic specialization is important to spermiation,
the translocation of spermatids, and possibly in the stabilization
of other junction types present between Sertoli and
Sertoli-spermatid cells,such as tight and desmosome-like junctions
19. 4.Tubulobulbar complexes.
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• It is modified type of the adherens junction, the tubulobulbar complex found between
Sertoli cells.
• The function of the tubulobulbar complex is to prevent the premature release of
elongate spermatids into the tubule lumen.
• Tubulobulbar complexes are intermingled(combines) between tight and gap junctions
during germ cell movement.
5.Desmosome like junctions
Desmosomes, cell-cell anchoring junctions that use
intermediate filaments as their attachment sites.
Desmosomes consists of proteins through which they
attatches sertoli cell with spermatid cells the proteins
are desmoplakins,desmogleins,plankoglobin.
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• Hemidesmosome is an intermediate filament-based cell-matrix anchoring junction type
found at the Sertoli cell.
• Hemidesmosomes are cell junctions that connect a cell’s cytoskeleton to the basement
membrane.
6.Hemidesmosomes
7.Gap Junction
Gap junctions are the means by which ions and small
molecules are exchanged between two adjacent cells.
Gap junctions mediate signals between Sertoli and germ
cells.
Gap Junction plays a crucial role in germ cell movement in
the seminiferous epithelium.
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21. Conclusion
• The sertoli cells provide nourishment to developing and maturing sperm cell so sertoli
cell is also called mother cell or the nurse cell.
• Sertoli and spermatid are interacted through the junctional complexes.
These junctions provide structural support ,passage of molecules and protect from
enzymes and other harmful substances by creating an impermeable barrier.
• Also it is broad subject to study in field of research the specific area of it deserves
future investigations and research.
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