Describe physiological functions of growth hormone Identify relationship between GH and insulin like growth factors (Somatomedins) Identify factors controlling secretion of growth hormone Discuss the abnormalities of growth hormone.

1. PhysiologicalFunctions
ofG
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Disorders
Dr
.AWAIS IRSHAD

2. LectureObjectives
• Describe physiological functions of growth hormone
• Identify relationship between GH and insulin like growth
factors (Somatomedins)
• Identify factors controlling secretion of growth hormone
• Discuss the abnormalities of growth hormone.

3. Actions of GrowthHormone
Growth Promoting
Actions
• Growth of almost all tissues of the
body
• Increase cell size (bone andmuscle
thickness)
• Promote mitosis to increase
number of the cells (bone length)
• Promotes differentiation ofcertain
types of cells
Metabolic Actions
• Increase rate of proteinsynthesis
• Increase mobilization of fattyacids
from adipose tissue
• Decrease rate of glucoseutilization
throughout thebody

4. Protein Metabolism
ANABOLIC ACTIVITY
• Promotes protein deposition in
tissues
• Increases amino acid uptake
• Enhancement of RNA translation
• Increases nuclear transcription of
DNA
• Decreases catabolism of protein
•Potent “ProteinSparer”

5. Fat Metabolism (LipolyticEffect)
• Increase fat breakdown
• Causes release of fatty acids
from adipose tissue
• Promote fat utilization for
energy
• Ability of GH to promote fat
utilization along with its protein
anabolic effect causes anincrease
in lean bodymass

6. CarbohydrateMetabolism
• Decreases glucose uptake in the tissues (skeletal muscle
and fat)
• Increases glucose production by liver
• Causes hyperglycemia
• Increase insulin secretion
• Increases insulin resistance (antagonist to insulin)
• GH effects are called Diabetogenic

7. Growth PromotingActions
• Adequate insulin & carbohydrates
are necessary for GH to act
effectively
• They provide energy needed for
the metabolism of growth
deposits
new bone on the surface of older bone
Bones continuously become
thicker throughout life even
after adolescence
Especially membranous bones

9. Growth Hormone (indirecteffect)
Most of the growth effects of GH result from IFG-1
rather than from direct effect of GH on bones and
tissues

11. Inc.gluconeogenesis
Inc.lipolysis

12. Abnormalities of GrowthHormone
Hypo secretion ofGH
• Dwarfism due to
Panhypopituitarism

13. African Pygmies
• Rate of growth hormone
secretion is normal or high
• Congenital inability to
synthesize IGF-1
• Causing small stature of
these people

14. Laron Dwarfism
• Mutation of the GH
receptor
• Failure of the GH to
stimulate IGF-1
production
• GH levels will be normal
or high
• IGF-1 levels low

15. Hyper secretion of
GH
• Tumor of Acidophilic cells of Ant. Pituitary
gland
• GH production is more
• Gigantism (excess GH before Adolescence)
• Acromegaly (excess GH after Adolescence)

16. Gigantism
• Excessive GH secretion before the
fusion of epiphyses
• excessive action of insulin-like growth
factor I (IGF-I)
• Height increases upto 8 feet tall
• Hyperglycemia
• Degeneration of beta cells of pancreas
• Full blown diabetes

17. Acromegaly
• Excessive GH secretion after
the fusion of epiphyses
• Person cannot grow taller but
bone thickening will occur
• Bone thickness especially in
hands feet and membranous
bones
• Changes in vertebrae
causes hunched back -
Kyphosis

18. An 11 year old kid comes to doctor with obesity
and dwarfism. He needs the administrationof
• Catecholamine
• Growth
hormone
• GHRH
• IGF-1
• Somatostatin

19. Factor decreasing the growthhormone
secretion
• Deep sleep
• Estrogen
• Exercise
• Hyperglycemi
a
• Protein meal

20. Which of the following are correct regarding the
effects of increased levels of growth hormone in
acromegaly?
• Increased levels of growth hormone stimulate increased
production of IGF1 from the adrenal glands
• Increased levels of growth hormone stimulate increased
production of ADH from the adrenal glands
• Increased levels of growth hormone stimulate increased
production of ADH from the liver
• Increased levels of growth hormone stimulate increased
production of IGF1 from the liver

21. Thank you………
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