The hormones controlling the female reproductive system include gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH) and leutenizing hormone (LH), all of which are produced in the brain; oestrogen and progesterone produced by the ovaries and the corpus luteum; and human chorionic gonadotropin (HCG).

1. ANIMAL PHYSIOLOGY
WEBINAR
TOPIC- HORMONAL CONTROL OF
REPRODUCTIVE PROCESS IN FEMALES
BY
AHMED NUSAIM
20-PZO-004
14th SEP 2021 1

2. SYNOPSIS
● Introduction To Hormones
● What Are Reproductive Hormones?
● Ovarian Hormones
➡Estrogen
➡Progesterone
● Gonadotropin -Releasing hormone (GnRH)- FSH & LH
● Role of Hormones Prolactin And Oxytocin
● Summary
● Video
● References
● Question Bank
2

3. INTRODUCTION TO HORMONES
A Hormone is a Chemical messages that is released into the blood and transported to
affect cells in other parts of the body
Hormones Regulate many things in the body such as:
● Growth and Development
● Male and Female Development
● How the body uses the energy
● Levels of salts and sugars in the blood
● The amount(Volume) of fluid in the body
3

4. WHAT ARE REPRODUCTIVE HORMONES?
● Certain Hormones play a key role in the process of reproduction.
● They cause different sexual characteristics in males and females and control
fertility or the ability to have offspring
● There are several Reproductive Hormones but the major ones are Estrogen,
Progesterone, and Testosterone .
● These Hormones are associated with the Puberty.
4

5. OVARIAN HORMONES
Ovarian function is driven by the two pituitary gonadotropins :follicle-stimulating
hormone (FSH) and luteinizing hormone (LH) which stimulate:
● Ovarian steroid production
● Growth of the follicle
● Ovulation
● and development of the corpus luteum
The principal hormones secreted by the ovary are:
estrogens (estradiol and estrone) and progesterone
● These hormones are steroids and are derived from cholesterol by the series of
reactions
● Their biosynthesis is complexly linked with the events of the ovarian cycle
5

6. ESTROGENS
● HISTORY: During the Extensive studies of sex hormones, in the 1920s,American
Biochemist Edward Doisy , discovered how to isolate and purify Oestrogens.
● STRUCTURE OF ESTROGEN:
● The estrogens are C-18 steroids and differ from androgens in lacking the methyl
group C10. The ring A is aromatic.
● The androgens, testosterone, and androstenedione are precursors for the synthesis
of the estrogens in testis, ovaries, adrenals and placenta.
6

7. FUNCTIONS OF ESTROGENS
● Estrogens are responsible for the growth of the uterus, vagina, pelvis, breasts, pubic and
axillary hair.
● They influence the menstrual cycle and are essential for breast development.
● They influence the secretion of the gonadotrophs hormones in the anterior pituitary.
● They increase the plasma levels of thyroxine and Cortisol binding globulins.
● They cause rapid increase in RNA synthesis in uterine tissue.
● They prevent lipid accumulation in liver when administered to animals having diets
deficient in lipotropic factors i.e. methionine and choline.
● They cause decrease in cholesterol level and other lipids in plasma. This is why the
incidence of atherosclerosis is low in women as compared to men.Normally the females
excrete estrogens 5-100 Hg/24 hours in urine. 7

8. PROGESTERONE
HISTORY:
In 1925, German Biochemist ,Adolf Butenandt , isolated Progesterone, another
important sex hormone ,from the urine of Pregnant women. Progesterone prepares the
uterus for Pregnancy . A sudden fall in progesterone is one of the several events that
trigger labor.
ORIGIN OF PROGESTERONE:
● This hormone is formed in the corpus luteum of the ovary. It is also formed in the
placenta during the latter part of pregnancy. It is secreted 1 or 2 days before
ovulation takes place. 8

9. PROGESTERONE
STRUCTURE OF PROGESTERONE:
● It is synthesized from cholesterol.
● It is also formed in the adrenal cortex as a precursor of both C-19 and C-21 9

10. FUNCTIONS OF PROGESTERONE
● Progesterone causes the development of the endometrium preparing it for the im-
plantation of fertilized ovum for conception
● It suppresses oestrus, ovulation and the production of luteinizing hormone. When
pregnancy occurs, the ovulation and menstruation are suspended by the action of
this hormone.
● It stimulates the mammary glands.
● It increases BMR during the luteal phase of normal menstrual cycle.
● In the normal menstrual cycle, the anti-ovulatory effect of progesterone is the basis
for the use of certain synthetic progestin’s as oral contraceptive agents.
● The normal level of progesterone in serum is 0.2-1.5 mg/ml.
10

11. IMAGE
11
Produced by the
ovaries, progesterone
is referred to as the
“pregnancy hormone”
because it helps a
woman's body achieve
and maintain
pregnancy

12. STRUCTURE OF MATURE OVUM
● Human Ovum is small. It contains no Yolk ( Alecithal egg). It is more than 100µm
in diameter. At the time of ovulation, ovum is surrounded by a striated membrane
called Zona radiata and later is replaced by Zona Pellucida (Primary Egg
Membrane)
● The Growing oocytes are surrounded by follicular cells . Some of the follicular
cells of the ovary are found outside the zona pellucida and are termed as Corona
radiata( Secondary Egg membrane)
● The follicles and the developing oocyte together constitute Graafian follicle . The
whole surface of the graafian follicle is supported by theca interna and theca
externa .
12

13. HUMAN OVUM
13

14. PROCESS OF OVULATION
● The Shedding of the ovum from the ovary is called as Ovulation. The ovarian
follicle enlarges and reaches the surface of the ovary. The stroma and the theca of
the graafian follicle rupture and the ovum is shed from the ovary.
● As it reaches the fallopian tube it may get fertilized . The fertilized egg reaches the
uterus and gets implanted on its wall. If the ovum is not fertilized in the fallopian
tube it dies in 12-24 hours.
CORPUS LUTEUM:
● The corpus luteum is an important structure needed at the time of pregnancy.It is
derived from the empty graafian follicle after ovulation.The corpus luteum secrete
a hormone called as Progesterone.
● It is a steroid hormone ,secreted in significant amounts by corpus luteum and
placenta 14

15. PROCESS OF OVULATION
15

16. GONADOTROPIN RELEASING HORMONE
● Gonadotropin-releasing hormone is produced and secreted by specialised nerve cells
in the hypothalamus of the brain.
● It is released into tiny blood vessels that carry this hormone from the brain to the
pituitary gland, where it stimulates the production of two more hormones – follicle
stimulating hormone and luteinising hormone.
● These hormones are released into the general circulation and act on the testes and
ovaries to initiate and maintain their reproductive functions
● Follicle stimulating hormone and luteinising hormone control the levels of hormones
produced by the testes and ovaries (such as testosterone, oestradiol and
progesterone), and are important in controlling the production of sperm in men and
the maturation and release of an egg during each menstrual cycle in women. 16

17. FOLLICLE STIMULATING HORMONE
● It is a gonadotropic hormone that directly stimulates the gonadal functions in both males and
Females.Human FSH is a small glycoprotein . The Target organs for FSH in females are the
ovaries.
● It promotes the growth of graafian follicle and thereby increases the total weight of the ovary.
It also promotes the secretion of Oestrogen
● In males the target organs for FSH are the testes.
● It Directly stimulates the germinal epithelium of the seminiferous tubules and augment the
rate of spermatogenesis
17

18. LUTEINIZING HORMONE
● Human Interstitial Cells Stimulating Hormone or LH is a glycoprotein .
● In females , the Luteinizing Hormone stimulates the ripening of ovarian
follicles and induces ovulation.
● In males, the Luteinizing Hormone or ICSH specifically affects the
Leydig cells or Interstitial cells of the testes and stimulates the synthesis
and secretion of male hormone ( Androgen) Testosterone.
● These two hormones are secreted by the Anterior Adenohypophysis of
Pituitary Gland ( Master Gland)
18

19. FSH AND LH EFFECT ON OVARY
19

20. ROLE OF HORMONE PROLACTIN
● In addition to producing FSH and LH, the anterior portion of the pituitary gland
also produces the hormone prolactin (PRL) in females.Prolactin is called by
several names like Luteotropin ,luteotropic hormone , lactogenic hormone
,mammotropin etc. It is a protein hormone
● It’s main function is stimulation of milk formation or initiation of lactation
following parturition in mammals.
● It also stimulates the corpus luteum to secrete the Progesterone.
● Prolactin together with Oestrogen stimulates the growth of mammary glands and
makes it ready for milk secretion.
20

21. ROLE OF HORMONE OXYTOCIN
● Oxytocin contains Sequence of amino acid residues. The term “Oxytocin”
refers to rapid birth.
● This hormone directly stimulates the smooth muscles of uterus and causes the
contraction and helps in the delivery of Foetus.
● Another major Physiological function of Oxytocin is the secretion of milk
from the lactating breast.Oxytocin stimulates the myoepithelial cells ,which
surrounds the alveoli and ducts of mammary gland
● The contraction of myoepithelial elements in turn expels the milk from the
alveoli of the breast into the larger ducts or sinuses .
● From the sinuses , the milk is ejected out. 21

22. OXYTOCIN & PROLACTIN
22

23. SUMMARY
● The reproductive system is controlled by the gonadotropins follicle-stimulating
hormone (FSH) and luteinizing hormone (LH), which are produced by the pituitary
gland. Gonadotropin release is controlled by the hypothalamic hormone
gonadotropin-releasing hormone (GnRH)
● FSH stimulates the maturation of sperm cells in males and is inhibited by the
hormone inhibin, while LH stimulates the production of the androgen testosterone.
FSH stimulates egg maturation in females, while LH stimulates the production of
estrogens and progesterone.
● Estrogens are a group of steroid hormones produced by the ovaries that trigger the
development of secondary sex characteristics in females as well as control the
maturation of the ova. In females, the pituitary also produces prolactin, which
stimulates milk production after childbirth, and oxytocin, which stimulates uterine
contraction during childbirth and milk let-down during suckling. 23

24. VIDEOS
24
https://youtu.be/WXzsJcoIt2M https://youtu.be/pz2WTIlKhHQ

25. ANSWER OR HANDS DOWN
1. Where do FSH, LH and prolactin get released from ?
a) Ovaries
b) Uterus
c) Pituitary Gland
1. What does Inhibin (Secreted from Ovaries) do?
a) Inhibit FSH and GnRH
b) Stimulate FSH and GnRH production
25

26. ANSWER OR HANDS DOWN
3. Which hormone causes release of progesterone?
a) Prolactin
b) Oestrogen
c) Prostaglandin
4. The hormone that stimulates uterine contractions is
a. oxytocin
b. Estrogen
c. granular cell carcinoma
d. progesterone
26

27. ANSWER OR HANDS DOWN
5. What hormone causes lysis of Corpus Luteum and Uterine Contractions?
a) Prolactin
b) Cortisol
c) Prostaglandin
d) Oxytocin
6. What hormone is released due to FERGUSON's REFLEX when the foetus is pushed
caudally and stimulates further MYOMETRIAL contractions....
a) Prostaglandin
b) Oxytocin
c) Cortisol
d) Prolactin 27

28. QUIZ ANSWERS
1.c) Pituitary Gland
2.a) Inhibit FSH and GnRH
3.b) Oestrogen
4.a) Oxytocin
5.c) Prostaglandin
6.b) Oxytocin
28

29. REFERENCES
● https://courses.lumenlearning.com/wm-biology2/chapter/hormonal-
regulation-of-the-reproductive-system/
● https://www.biologydiscussion.com/hormones/types-of-female-sex-
hormones-2-types/43985
● https://www.slideshare.net/abhishekdahal/reproductive-hormones-
33210142
● https://www.slideshare.net/msthomas79/hormones-reproduction
● https://www.yourhormones.info/hormones/gonadotrophin-releasing-
hormone/
● Verma P.S ,B.S. Tyagi and U.V.Agarwal ,2005 .Animal Physiology
.S.Chand & Company Ltd. New Delhi. 29

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