The biochemistry and physiology of FSH, LH and Testosterone.

1. FOLLICLE STIMULATING
HORMONE(FSH), LUTEINIZING
HORMONE(LH) &
TESTOSTERONE
BY: HERMAN NDJAMEN

2. PREVIEW
1. DEFINITION OF HORMONES
2. BIOCHEMICAL CLASSIFICATION OF HORMONES
3. CASE STUDIED
- Structure & classification
- Origin of production
- Target tissues/organ(s) and functions
- Mechanism of action
- DISEASES

3. DEFINITION: Hormones are chemical substances synthesized
in small amounts by endocrine tissues and carried by blood
stream to another tissue, where it acts as a messenger to
regulate the function of the target tissue or organ.
CLASSIFICATION OF HORMONES
CLASSES OF HORMONES CHEMICAL COMPOSITION EXAMPLES
AMINO ACIDS DERIVATIVES C, H and N, AMINE GROUP CATECHOLAMINES
POLYPEPTIDES
LONG CHAINS OF AMINO
ACIDS
INSULIN, GLUCAGON
GLYCOPROTEINS
LARGE PROTEINS COMBINED
WITH CARBOHYDRATES
FSH, LH etc
STEROIDS LIPIDS CORTICOIDS, SEX HORMONES
FATTY ACID DERIVATIVES
(EICOSANOIDS)
LONG HYDROCARBON ACID
CHAINS
PROSTAGLANDINS,
LEUKOTRIENES
&THROMBOXANES

4. CASE STUDY I: FOLLICLE STIMULATING
HORMONE (FSH)
A. STRUCTURE AND CLASSIFICATION.
FSH is a glycoprotein composed of 2
monomeric subunits proteins to which
is attached a sugar. The dimer contains
2 polypeptides; Alpha subunit made up
of 92 amino acids and a beta subunit
made up of 111 amino acids. This beta
subunit confers the hormone its
specific biologic action and is
responsible for interaction with FSH
receptors.
The sugar part of FSH is composed
of fucose, galactose, mannose, galacto
samine, glucosamine, and sialic acid
Normal level: 3mIU/ml – 10mIU/ml

5. ORIGIN OF PRODUCTION
The hormone is produced in
the pituitary gland(anterior)
under the influence of
Gonadotropic hormone
releasing hormone (GnRH)
produced in the
hypothalamus, inhibited by
inhibin and enhanced by
activin.
FSH is then released to the
blood stream towards the
target tissues.
It has a plasma half life of 3-4
hours

6. TARGET TISSUES AND FUNCTIONS
• FSH regulates the development, growth, pubertal
maturation, and reproductive processes of the
human body.
• In both males and females, FSH stimulates the
maturation of germ cells.
• In males, FSH induces Sertoli cells to
secrete inhibin and stimulates the formation of
sertoli-sertoli tight junctions (zonula occludens).
• In females, FSH initiates follicular growth,
specifically affecting granulosa cells

7. MECHANISM OF ACTION
• FSH binds to FSH-R on the cell
membrane.
• This occupied receptor causes
replacement of GDP bound to Gs
protein by GTP, activating this Gs
protein.
• Gs alpha subunit moves to
ADENYLATE CYCLASE. This cyclase
then catalyzes formation of cAMP
(second messenger) from ATP
• The CAMP then activates protein
kinase (third messenger), which in
turn by phosphorylation of cellular
proteins influences on mRNA
synthesis.

8. DISEASES
1.HIGH LEVELS OF FSH
• Premature menopause also known as Premature
Ovarian Failure
• Poor ovarian reserve also known as Premature
Ovarian Aging
• Gonadal dysgenesis, Turner syndrome (XO)
• Castration
• Swyer syndrome(46XY but externally female)
• Certain forms of CAH
• Testicular failure.
• Klinefelter syndrome(XXY)

9. 2. LOW LEVELS OF FSH
1.Polycystic Ovarian Syndrome
2.Polycystic Ovarian Syndrome + Obesity +
Hirsutism + Infertility
3.Kallmann syndrome (incomplete puberty)
4.Hypothalamic suppression
5.Hypopituitarism
6.Hyperprolactinemia
7.Gonadotropin deficiency

10. CASE STUDY II: LUTEINIZING
HORMONE(LH)
A.STRUCTURE AND CLASSIFICATION
LH is a heterodimeric glycoprotein.
Each monomeric unit is
a glycoprotein molecule; one alpha and one
beta subunit make the full, functional
protein. The alpha subunit is similar in all
glycoprotein hormones but it’s beta subunit
consists of 120 amino acids, that confers its
specific biologic action and is responsible
for the specificity of the interaction with
the LH receptor. The carbohydrate part
consist of different oligosaccharides
The biologic half-life of LH is 20 minutes.
During the reproductive years, typical levels
of LH are between 1-20 IU/L.
In males over 18 years of age, reference
ranges have been estimated to be 1.8-8.6 IU/L

11. ORIGIN OF PRODUCTION
LUTEINIZING HORMONE is produced in the
pituitary gland under the regulation of
GONADOTROPIC HORMONE RELEASING
HORMONE(GnRH). It is then released to the
blood stream towards the target tissues

12. TARGET TISSUES AND FUNCTIONS
In females, LH supports theca cells in the ovaries that
provide androgens and hormonal precursors for estradiol
production.
-"LH surge" triggers ovulation, thereby not only releasing
the egg from the follicle, but also initiating the conversion of
the residual follicle into a corpus luteum that, in turn,
produces progesterone to prepare theendometrium for a
possible implantation.
In the male, LH acts upon the Leydig cells of the testis and
is responsible for the production of testosterone,
an androgen that exerts both endocrine activity and
intratesticular activity on spermatogenesis.

14. MECHANISM OF ACTION
• The mechanism of action is basically similar to
that seen in FSH and the diseases observed
too.

15. SWYER SYNDROM:
HIGH FSH AND LH
levels in blood.

16. HIGH LEVEL OF LH (low level of FSH) in female and male

17. CASE STUDY III: TESTOSTERONE
STRUCTURE AND CLASSIFICATION
Testosterone is made up of
CYCLOPENTANEPERHYDROPH
ENANTHRENE ring which is a
characteristics of most steroid
hormones.
Therefore testosterone is
considered to be a steroid
hormone with molecular
weigh (MW) = 288,4

18. ORIGIN OF PRODUCTION
TESTOSTERONE is primarily produced in the
testes by the INTERSTITIAL CELLS OF LEYDIG.
Precursor of testosterone is Progesterone
which is first converted to androstenedione
which is then hydrolyzed to form
testosterone. This is how testosterone is
produced in females.
Testosterone is also produced in small
amount in the zona reticularis of the adrenal
gland.
Testosterone level is regulated by FSH and
LH.
LH stimulates an increase in number of leydig
cells , hence increasing testosterone level, and
vice versa.
Testosterone is transported together with
specific plasma protein binding globulin or
testosterone-estrogen binding globulin

19. TARGET TISSUES AND FUNCTIONS
Testosterone acts on several tissues of the body
where it carries out the following functions:
1. It is responsible for gonadal development in the male
embryo.
2. This hormone is responsible for "brain masculinization"
in infant boys.
3. It is responsible for secondary sexual characteristics in
male.
4. It increases energy metabolism, thereby helping men to
shed extra pounds, lower their body fat, and acquire a
leaner and fitter physique.
5. Testosterone is also believed to stimulate erythropoeisis

20. MECHANISM OF ACTION

21. DISEASES
• LACK OF TESTOSTERONE: this induces
hypogonadism (primary- testicular failure)
• Normal level of testosterone but defective
receptors induces “ testicular feminization” I.e
genotype is XY but phenotype is female (swyer
syndrom).

22. HYPOGONADISM: Deficient LH activity

23. THANKS FOR
YOUR
ATTENTION