Male hormones by Suyash Garg. M.Sc. 2nd Semester. National University Amarkantak M.P.

1. Presentation Topic - MALE HORMONES.
Presented by Suyash Garg M.Sc. 2nd Semester.
Paper - Molecular Endocrinology
Department of Zoology I.G.N.T.U. Amarkantak (484887)
M.P.

2. Content
1.Introduction to male hormones.
2.Gnrh Gonadotropin Releasing Hormone
.Production,Secretion and Function.
3. Leutinizing Hormone LH and Follicle Stimulating Hormone. FSH
.Release and its Functions.
4. Negative Feedback Mechanism and Role of Inhibin.
5. Testosterone Production And Function
6.Testosterone Dysfunction.
. Conclusion

3. Male hormones
What are hormones?
Hormones are chemical substances which are used for transmitting messages from one
part of the body to the other through blood circulation. Hormones are for growth,
reproduction and well-being.
Androgens are the group of sex hormones that give men their 'male' characteristics .
The major sex hormone in men is testosterone, which is produced mainly in the testes.
• Androgens are male sex hormones that increase at puberty.
• Testosterone is the most important androgen (male sex hormone).
• Testosterone. Testosterone is the major sex hormone in men .
• Control Hormones - FSH & LH. Follicle stimulating hormone (FSH) and luteinising
hormone (LH), production begins in the brain. .
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4. • The reproductive hormonal axis in male consists of three main components:
the hypothalamus, the pituitary gland and the testes.
• These functions in regulated manner to produce concentrations of circulating
hormones required for normal male sexual development, sexual function and
in male fertility.
• Hormones produced by this axis include the hypothalamic gonadotropin
releasing hormone GnRH, pituitary gonadotropins FSH and LH and testicular
steroids.
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5. GONADOTROPIN-RELEASING HORMONE
Gonadotropin-releasing hormone (GnRH) is small neuropeptide .It is composed of 10 amino
acids, so it is called decapeptide hormone.
GnRH amino acid sequence
Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly
GnRH is synthesized as part of a large prohormone that is cleaved enzymatically and
further modified within the secretory granules. GnRH is degraded by proteolysis within
few minutes, so it has a short half-life, approximately 2-4 min.
The gene, GnRH1, for the GnRH precursor is located on chromosome 8.
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6. Production & Secretion of GnRH from Hypothalamus to Pituitary:
• GnRH is considered a neurohormone, a hormone produced in a specific neural cell that are
distributed throughout the hypothalamus and released at its neural terminal.
• A key area for production of GnRH is the of the hypothalamus, which
contains most of the GnRH- secreting neurons.
Testosteorone
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7. • GnRH is secreted from median eminence into capillary of Portal circulation to the
anterior pituitary.
• The neuron kisspeptin in preoptic area of hypothalamus signals directly to hypothalamic
neuron via kisspeptin receptor to release GnRH to portal circulation.
• This GnRH secretion occurs in
pulsatile manner.
• Pulsatile activity can be
disrupted by hypothalamic-
pituitary disease, either dysfunction.
male
gonads
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8. LH and FSH release and their function:
After stimulated by GnRH the Gonadotrop cell release LH and FSH into the blood.
After that it reaches to target organ male gonads Testes.
LH - stimulates Laydig cells of the testes to secrete testosterone hormone.
FSH - stimulates sertoli cell in semniferous tubule of testes to formation
of sperm.
fig. Semniferous tubule
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t.s.of Testes

9. (Negative Feedback Control of Semineferous Tubule Activity- Role of the Hormone Inhibin)
• When the semineferous tubule produce sperm in low quantity then secretion of FSH by the
anterior pituitary gland increases .
• And when spermatogenesis proceeds too rapidly, pituitary secretion of FSH decreases. The
cause of this negative feedback effect on the anterior pituitary is secretion by the Sertoli
cells of semniferous tubule of testes another hormone
called Inhibin .
• This hormone has a strong direct effect on
the anterior pituitary gland to inhibit the secretion of
FSH and possibly a slight effect on the hypothalamus
to inhibit secretion of GnRH.
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10. Testosterone
Testerones a steroid hormone from the androgen group.
In mammals, testosterone is primarily secreted in the testes of males.
An androgen is natural or synthetic steroid hormone that regulates the development and
maintenance of male characteristics in vertebrates.
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The testosterone biosynthetic pathway
occurs in the laydig cell of Mitochondria &
SER, starting from cholesterol. Cholesterol is
transformed to pregnenolone after the
cleavage of its side chain. Pregnenolone is
then converted in androstenedione and finally
in testosterone
Biosynthesis of Testosterone from Cholestrol.

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12. FUNCTION OF TESTOSTERONE
During fetal development:
1- Causes formation of the prostate gland, seminal vesicles and
male genital ducts.
2- Suppressing the formation of female genital organs.
Before puberty
1.Before puberty, effects of rising androgen levels occur in boys.
These include adult-type body odor, increased oiliness of skin and hair, acne
During puberty development:
1 -Causes enlargement of scrotum and testes.
2- Influence the secondary male sex characteristics as aggressive behavior and
body hair patterns.
3 - Stimulates protein buildup in muscles production muscular development.
4 - Causes enlargement of the thyroid cartilage, resulting in the visible Adam's
apple in males and deepening of the voice.
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13. Testosterone Dysfunction 11

14. Conclusion
1.The hypothalamic produces gonadotropin-releasing hormone (GnRH),
2.Travels down the anterior part of pituitary gland via hypophysial portal
system and bind to receptor on the secretary cells of adenohypothysis
3.In response to (GnRH) stimulation these cell produce (LH) and (FSH)
which travel into blood stream.
4.In male (LH) stimulate the interstitial cells located in the test is to
produce testosterone and (FSH) play role in spermatogenesis.
5.Testosterone is required in the male development primary and
secondary male characters. Such as Facial hair growth, deep
voice.
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15. Thankyou For Your Attention