علم راهی بسوی آفریدگار جهان Growth Hormone (GH; Somatotropin) Dr. Radmanesh
Human Growth Hormone Polypeptide 191 amino acid residues MW = 22125 daltons Highly hydrophobic proteins
Regulation of GH Expression in Somatotrophs GHRH somatostatin AC Gs Gi (-) cAMP PKA PIT-1 GH synthesis A txn factor in the Pit
Actions of Growth Hormone: increases skeletal growth increases muscular growth increases amino acid uptake and protein synthesis increased use of lipids for energy decreased storage of carbohydrates 3
Feedback control of growth hormone
ganong Ganong
Ganong
Downloaded from: StudentConsult (on 15 June 2006 06:30 AM) © 2005 Elsevier
Downloaded from: StudentConsult (on 15 June 2006 06:30 AM) © 2005 Elsevier
Downloaded from: StudentConsult (on 15 June 2006 06:30 AM) © 2005 Elsevier
Ganong
Amount of Growth Hormone
CLINICAL PICTURE OF HYPOPITUITARISM DEPENDS ON HORMONES LOST 1. Lack of FSH LH : 1. Hypogonadim 2. Lack of TSH: hypothyroidism 3. Lack of ACTH: adrenocortical insufficiency 4. Prolactin deficiency 5. If all of the above: PANHYPOPITUITARISM 6. In children: GH: short stature
Cause of Hypopituitarism Shock or severe hypotension Head trauma Brain tumors or infection Genetic considerations
What Causes this Disorder? Hyposecretion (underproduction) of the Growth Hormone during growing years causes slow bone growth and the epiphyseal plates close before normal height is reached. This condition is known as Dwarfism.
Laron dwarfs, who lack normal GH receptors but have normal GH secretion.
Care Replacement of deficient hormones Androgen therapy Estrogens and progesterone Growth hormone
Hyperpituitarism Hormone oversecretion occurs with pituitary tumors or hyperplasia Genetic considerations Pituitary adenoma
Gigantism Gigantism is the onset of growth hormone hypersecretion before puberty.
Acromegaly
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Complications of Acromegaly Cardiovascular Ischemic heart disease Cardiomyopathy Congestive heart failure Arrhythmias Hypertension Respiratory Kyphosis Metabolic Diabetes mellitus/IGT Hyperlipidemia http://www.endotext.com/neuroendo/neuroendo5e/neuroendoframe5e.htm
Patient-Centered Collaborative Care Assessment Nonsurgical management: Drug therapy- to reduce GH secretion or the effects on tissues Somatostatin analogues Dopamine agonists Growth hormone antagonist Radiation Gamma knife procedure Usually one time treatment
Surgical Management
Pituitary Surgery