1. Growth Hormone
Prof. K. Sivapalan

2. Growth Hormone 191 amino acids, mw- 21500, half life- 20minutes.
Mechanism of action-
Direct and through somatomedins- Insulin like Growth Factor I, II. [IGF- I, IGF- II.]
Growth hormone

3. Effects on Protein metabolism.
Increase in AA transport in to cells.
Increase in protein synthesis.
increase RNA synthesis.
Decrease catabolism of protein.
Growth hormone

4. Effects on Fat metabolism.
Increase lipolysis from adipose tissue.
Fatty acids breakdown for energy increased.
Ketone body formation increased.
Growth hormone

5. Effects on Carbohydrate Metabolism.
Reduce utilization of glucose for energy.
Increase glycogen synthesis.
Decrease glucose uptake by tissues.
Growth hormone

6. Effects on bone Increases chondrogenisis. increases mineralization.
Growth hormone

7. General effects Increased metabolic rate. decreases plasma cholesterol
decreases Na, K excretion.
positive nitrogen balance
reduces blood urea, amino acids.
Growth promotion requires insulin and glucose.
Growth hormone

8. Control of Secretion. GHRH from hypothalamus-release.
Somatostatin- inhibition.
Regulation- feedback- IGF-I reduce GH release and increase Somatostatin release.
Growth hormone

9. Other stimuli that increase secretion:
Deficiency of energy substrate-
hypoglycaemia.
exercise
fasting
2 Deoxyglucose.
Amino acids-
protein meal
infusion of arginine and other amino acids.
Glucagon
Stress-
pyrogens
psychologic stresses.
Sleep- non REM sleep.
Estrogens and androgens
Growth hormone

10. Other stimuli that decrease:
REM sleep.
Glucose
Cortizol
FFA
Also spikes of secretion occur without recognizable stimuli- pulsatile release.
Growth hormone

11. Hypopituitarism in Adults
lethargy- thyroid function.
weight gain- fat deposition.
loss of sexual functions- gonadotropins.
reduced pigmentation- ACTH
Growth hormone

12. Hypopitutarism in children
Dwarfism-.
delayed growth.
puberty may or not occur.
mental function is good.
Difficulties may occur at times of stress.
Growth hormone

13. Hyperpitutarism Usually due to tumor Effect on visual field
By-temporal hemianopia.
Growth hormone

14. Acromegaly: in Adults. Thick small bones of limbs.
Thick membrane bones- cranium, nose, forehead, supra orbital ridges, lower jaw.
Vertebra- kyphosis.
Soft tissues- increased size - tongue, liver, kidney.
Hyperglycaemia.
Visual field defect.
Growth hormone

15. Acromegaly
Growth hormone

16. Gigantism: in children
Rapid growth.
Hyperglycaemia.
Growth hormone

17. GROWTH Genetic factors. Nutrition Growth hormone. Thyroid hormone.
Insulin.
Corticosteroids.
Sex hormones.
Growth hormone