A hormone is a chemical released into the
blood and transported to affect cells in other
parts of the body.
Hormones regulate many things in the body,
•Growth and development.
•Male and female development.
•How the body uses energy.
•Levels of salts and sugars in the blood.
•The amount (volume) of fluid in the
•Certain hormones play key
roles in 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 ,
•these hormones are
associated with puberty
• Puberty is the process of physical changes by
which a child's body becomes an adult body
capable of reproduction.
• Puberty is initiated by hormone signals from
the brain via the pituitary gland to the ovaries
of the females and testes of the males. In
response, these organs produce a variety of
hormones that stimulate the growth, function,
or transformation of brain, bones, muscle,
skin, breasts, and reproductive organs.
Source: Ovary, Placenta and Testis.
(Estrogens are hormones found in
females and in low levels in males.)
Types: 17-β Estradiol, Estrone and
1. Growth and development of fallopian
tubes, uterus, vagina, external genitalia.
In females, estrogens control the
development of secondary sex
2. These hormones control different stages
of the menstrual cycle in females.
3. In males and females estrogen promotes
normal bone development and density.
4. Estrogen inhibits LH release.
Men: 30-200 pmol/l.
• During the extensive studies of sex hormones
in the 1920s, American biochemist, Edward
Doisy, discovered how to isolate and purify
The Structure of Estrogen
Compounds that have this basic 4-ring structure of
carbon atoms are called “steroids.” The side chains of
H and OH distinguish the different kinds of steroids.
Five years later, 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 several
events that triggers labor.
• Source: Corpus luteum, Adrenal
• Normal level : 6-60 nmol/l
1. Stimulation & growth of mammary
2. Plays role in conception and
maintenance of pregnancy.
3. Inhibition of FSH & LH.
How estrogens and progesterone achieve their
Steroids like estrogens and progesterone are small,
hydrophobic molecules that are transported in the
blood bound to a serum globulin.
In "target" cells, i.e., cells that change their gene
expression in response to the hormone, they bind to
receptor proteins located in the cytoplasm and/or
The hormone-receptor complex enters the nucleus
and binds to specific sequences of DNA, called the
estrogen (or progesterone) response elements
How estrogens and progesterone achieve
Response elements are located in the
promoters of genes.
The hormone-receptor complex acts as a
transcription factor which
turns on (sometimes off) transcription of
Gene expression in the cell produces the
Menopause occurs in older
women when the ovaries stop
producing estrogen, resulting in
a stopping of menstrual cycles
and loss of fertility.
Postmenopausal women receive
estrogen therapy to help prevent
bone loss and control symptoms
In this therapy, women are given
the estrogen their ovaries no
• Hormone replacement therapy does more
than relieve symptoms of menopause.
• It has been shown that bone fractures
decrease by 50 – 70% and bone density
increases by ~5%.
• Also cardiovascular disease is less prevalent
in women who receive this therapy.
• The most serious drawback of hormone
replacement therapy are blood clots.
• These can be dangerous if they occur in the
circulatory system because they can block
Testes or Ovaries
or Estrogen &
Testosterone, like estrogen, is also a steroid hormone. It is
found in males and in smaller amounts in females.
In males, testosterone controls the development of
secondary sex characteristics such as facial hair and
increased muscle mass.
Testosterone in males is produced by the testicles.
Compare and contrast the characteristics of these male
animals to the females you observed earlier.
• Testosterone was
purified by Ernst
Laqueur at the
Amsterdam in 1934
from bull reproductive
• Testosterone was then isolated in 1935 by
Karoly David, E. Dingemanse, J. Freud and
• Butenandt, who was also involved in estrogen
research, studied testosterone and
chemically synthesized it and worked out its
• Fetal : Differentiation of wolffian
ducts into epididymis, vas deferens
and seminal vesicles.
• Descent of testis. (cryptorcidism)
• Development of 2ndry sexual
• Anabolic effect : increase in muscle
mass, stimulation of erythropoiesis
• Erectile function & initiation of
1. Infertility in males:
Causes: Hypogonadism and Dis.
affecting Sperm synthesis &
Diagnosis: Measurement of sex
hormones, gonadotropins and sperm
3. Prostrate Hypertrophy and Cancer:
Due to DHT hypersecretion for
mainly to patient above 60 yrs.
Treatment- Fenasteride :analogs
that inhibits enz(5 alpha reductase)
required for conversion of DHT
or structure analogs that inhibts
FSH and LH secretion.
• If prostate cancer is
present, an increase of
growth in cancerous tumors
• It can also cause an absence
of sperm, an excess of red
blood cells, and sleep apnea
(when breathing completely
stops during sleep).
•These steroids are man made
derivatives of testosterone.
•Users of anabolic steroids include
athletes and body builders, who use
it to stimulate the body to build
muscle tissue and strengthen bones
and speed muscle recovery
following exercise or injury.
•Use of anabolic steroids is illegal
and extremely harmful.
Can you guess why they are
• Shrinking of the reproductive
organs, reduced sperm count, infertility.
Why do you think this happens?*
• Cancer, jaundice, liver tumors and high
blood pressure are the more serious risks.
• Aggression, acne, irritability, paranoia and
delusions can also occur.