Growth Hormone overview. Thanks to @marietoinette and @SeLipar PuTus for letting me share their slides.

3. TABLE OF CONTENT
Historical Note
Molecular level of GH
Development of Pituitary Gland
Histology of the Pituitary Gland
Hormones secreted from Pituitary Gland.
Parts of Pituitary Gland.
Pituitary Gland.
Diseases found in Pituitary Gland.
Diagrams.
Functions of Pituitary Gland.

4. The History of
the Pituitary
Gland.
•The earliest history of the pituitary gland
dates back to Ancient
Egypt (around 1365 BC) where a portrait, of the
Pharaoh at the time (Akhenaton), shows signs of
acromegaly. Galen, in 150 AD, was the first to
describe the pituitary, and he proposed that its
role was to drain the phlegm from the brain to
the nasopharynx.
•In the early 18th century, They pituitary-portal
blood system was dicovered.
• In 1772, Acromegaly was discribed. In
1794, Diabetes Insipidus was differentiated from
diabetes mellitus. In 1887, Minkowski was the
first to link the expansion of the pituitary
gland to a number of clinical symptoms. Within
a few years it was accepted that it was the

5. Development of Pituitary
Gland
• From 6-8 weeks :
• the neurohypophyseal bud grows inferiorly
from the hypothalamus
• the hypophyseal pouch grows superiorly
from the roof of the mouth (Rathke’s pouch)
• Neurohypophyseal bud becomes the
posterior lobe (neurohypophysis)
5-6 wks • Hypophyseal pouch becomes the anterior
pituitary (adenohypophysis)

6. Histology of Pituitary
Gland

7. Growth Hormone (GH)
Name : Growth hormone (also called
somatotropin)
Source of production : Adenohypophysis
(Acidophilic cells in pars distalis known as
somatotrophs).
Chemical structure : peptide hormone composed
of 191 a.a. presenting in many forms in plasma:-
1) Normal human GH (known as hGH n) M.W. 22000.
2) Variant human GH (known as hGH v) M.W. 20000.
3) Desamino forms : less active.

8. GH Functions
1. Stimulates division and multiplication of chondrocytes of
cartilage.
2. Increasing height in children and adolescents.
3. Increases calcium retention, and strengthens and increases the
mineralization of bone.
4. Increases muscle mass through sarcomere hyperplasia.
5. Promotes lipolysis.
6. Increases protein synthesis.
7. Stimulates the growth of all internal organs excluding the brain.
8. Plays a role in fuel homeostasis.
9. Reduces liver uptake of glucose.
10. Promotes gluconeogenesis in the liver.
11. Contributes to the maintenance and function of pancreatic islets.
12. Stimulates the immune system.

11. Regulation of GH
•
Secretion
Production of growth hormone is
modulated by many factors,
including stress, exercise, nutrition,
sleep and growth hormone itself.
However, its primary controllers are
two hypothalamic hormones and one
hormone from the stomach.
• Growth hormone-releasing
hormone (GHRH) is a
hypothalamic peptide that
stimulates both the synthesis
and secretion of growth
hormone.
• Somatostatin (SS) produced by
several tissues in the body,
including the hypothalamus,
inhibits GH release.
• Ghrelin secreted from the
stomach binds to receptors on

12. • Plasma GH • requires • GH binding
mechanism of action
mechanism of release
GH levels
level: in specific to two
children (5-8 signal GHRs causes
ng/ml) and in transductio dimerizatio
adults (2-4
ng/ml)
n systems n of
(cAMP GHR, activat
• Some factors
may elevate and/or ion of the
the level calcium GHR-
temporarily influx associated
as decrease in and/or JAK2
blood glucose mobilizatio tyrosine
and FFA levels n of kinase, and
- Fasting and intracellul tyrosyl
starvation ar calcium) phosphory
conditions -
and/ or lation of
physical
stress - sleep tyrosine both. These
- sex kinase(s) events
hormones. and/or recruit or

13. Growth hormone
uses
Agricultural Applications of Growth
Hormone: In the United States, it is legal to
give a bovine GH to dairy cows to increase
milk production, but it is not legal to use GH
in raising cows for beef, cattle
feeding, dairy farming and the beef hormone
controversy. Use in poultry farming is
illegal in the United States. Several
companies have attempted to have a version
of GH for use in pigs (porcine somatotropin )
approved by the FDA but all applications
have been withdrawn.
Replacement therapy: Treatment with
exogenous GH is indicated only in limited
circumstances, and needs regular
monitoring due to the frequency and
severity of side-effects. GH is used as
replacement therapy in adults with GH
deficiency of either childhood-onset (after
completing growth phase) or adult-onset
(usually as a result of an acquired pituitary
tumor). In these patients, benefits have
variably included reduced fat
mass, increased lean mass, increased bone
density, improved lipid profile, reduced
cardiovascular risk factors, and improved
psychosocial well-being.

15. A L
DEFINITION C Y
R
Chronic metabolic
O
disorder in which there is
M
too much growth hormone
E
and the body tissue
G
gradually enlarge
A

17. PATHOPHYSIOLOGY
Acromegaly is characterized by hypersecretion of growth
hormone (GH), which is caused by the existence of a
secreting pituitary tumor in more than 95% of acromegaly
cases. Pituitary tumors are benign adenomas and can be
classified according to size (microadenomas being less
than 10 mm in diameter and macroadenomas being greater
than 10 mm in diameter).3,4 In rare instances, elevated GH
levels are caused by extra pituitary disorders. In either
situation, hypersecretion of GH in turn causes subsequent
hepatic stimulation of insulin-like growth factor-1 (IGF-1).1

20. SYMPTOMS
Body odor glands ) Sleep apnea
Carpal tunnel Enlarge jaw and Swelling of bony
syndrome tongue areas around a joint
Decrease muscle Excessive height Thickening of
strength ( weakness skin, skin tags
) Excessive sweating
Widely spaced teeth
Easy fatigue Headache
Excess hair growth
Enlarge feet Hoarseness in females
Enlarge hands Joint pain Weight gain

21. DIFFERENTIAL DIAGNOSIS
Pseudoacromegaly
Presence of similar acromegaloid features
in the absence of elevated GH or IGF-I levels
Physiologic growth spurt during puberty
Familial tall stature or large hands and
feet
Myxedema

22. INVESTIGATION
Visual field tests
Assessment of other pituitary hormones: prolactin,
adrenal, thyroid, and gonadal hormones
MRI scan of pituitary and hypothalamus: more sensitive
than CT scan
CT scan: for lung, pancreatic, adrenal or ovarian tumours
that may secrete ectopic growth hormone or GHRH
Total body scintigraphy with radio-labelled OctreoScan®
(somatostatin) to aid localisation of the tumour

23. PROGNOSIS
Pituitary surgery is successful in most
patient, depending on the size of the tumor
and the experience of the surgeon
Without treatment the symptoms will get
worse,and the risk of cardiovascular
disease increase

24. COMPLICATIONS
Arthritis High blood pressure
Cardiovascular disease Sleep apnea
Carpal tunnel syndrome Spinal cord compression
Colonic polyps Uterine fibroids
Glucose intolerance or Vision abnormalities
diabetes

25. DEFINITION G S
I M
Abnormally large growth due
G
to an excess of growth
hormone during
A
childhood, before the bone N
growth plates have closed. T
I

27. CAUSES
The most common cause of too much growth hormone release is a
noncancerous (benign) tumor of the pituitary gland. Other causes
include:
Carney complex
McCune-Albright syndrome (MAS)
Multiple endocrine neoplasia type 1 (MEN-1)
Neurofibromatosis
If excess growth hormone occurs after normal bone growth has
stopped, the condition is known as acromegaly.

28. SYMPTOMS
Delayed puberty Irregular periods
(menstruation)
Double vision or difficulty
with side (peripheral) vision Large hands and feet with
thick fingers and toes
Frontal bossing and a
prominent jaw Release of breast milk
Headache Thickening of the facial
features
Increased sweating
Weakness

29. COMPLICATIONS
Delayed puberty
Difficulty functioning in everyday life due to large size and unusual features
Diminished vision or total vision loss
Embarrassment, isolation, difficulties with relationships, and other social
problems
Hypothyroidism
Severe chronic headaches
Sleep apnea

30. PROGNOSIS
Pituitary surgery is usually successful in
limiting growth hormone production.

32. EXAMS & TESTS
CT or MRI scan of the factor-I (IGF-I) levels
head showing pituitary
tumor Damage to the pituitary
may lead to low levels of
Failure to suppress other hormones, including:
serum growth hormone
(GH) levels after an oral Cortisol
glucose challenge Estradiol (girls)
(maximum 75g)
Testosterone (boys)
High prolactin levels

33. TREATMENT
Medications may be used to Sex hormone therapy, such as
reduce GH release, block the estrogen and
effects of GH, or prevent testosterone, which may
growth in stature. They inhibit the growth of long
include: bones
Dopamine agonists, such as Somatostatin analogs, such as
bromocriptine mesylate octreotide (Sandostatin) and
(Cycloset, Parlodel) and long-acting lanreotide
cabergoline (Dostinex), which (Somatuline Depot), which
reduce GH release reduce GH release
GH antagonist, pegvisomant
(Somavert), which blocks the
effects of GH

34. Other treatments of
gigantism
Radiation of the pituitary gland to regulate GH. This is
generally considered the least desirable treatment option
because of its limited effectiveness and side effects that can
include obesity, emotional impairment, and learning
disabilities.
Surgery to remove a pituitary tumor, which is the
treatment of choice for well-defined pituitary tumors.

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