Term
Growth Hormone and HP Axis |
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Definition
Hypo releases Growth Hormone Releasing Hormone (GHRH) It will cause Pit to release Growth Hormone Growth Hormone travels in Blood GH binds to receptors in tissues cause tissues to secrete IGF1 (insulin gorwth caftor 1) IGF1 circuates and binds to its receptors in other tissue to cause its own effects
Negative Feedback GH, IGF1 can bind to receptors on Pit and Hypo to inhibit release of GHRH from Hypo and GH from Pit Hypo can also secrete somatostatin that when binds to receptor on Pit, it will inhibit the release of GH.
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Term
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Definition
*GH secretion high in children, peaks at puberty, declines during adulthood Effects: Liver: inc gluconeogensis bone: stimulates longitudinal growth and inc bone mineral density Lipolysis muscle: inc muscle mass inc syn of IGF1 which goes and mimic effects of GH
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Term
| Therapeutic Uses of Growth Hormone |
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Definition
• Replacement therapy in short-stature children with or without GH-deficiency • Replacement therapy in adults with GH deficiency due to hypothalamic or pituitary defect • Symptoms associated with low GH levels: – Short stature – Increased circulating lipids – Reduced muscle mass – Reduced bone density – Reduced exercise capacity • AIDS-related wasting |
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Term
| Human Recombinant Growth Hormone |
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Definition
somatropins: amino acid sequence is that of native GH somatrem: altered amino acid sequence – daily subcutaneous administration – Most pronounced effects occur in first two years of use, after that theres not more effects Adverse effects: • mitogenic effects might activate latent malignancies – contraindicated for use within 2 yrs of any malignancy (not for ppl with leukemia) • children: intracranial hypertension, visual changes, leukemia • adults: peripheral edema, myalgia, arthralgia • Antibodies to exogenous GH develop so this will limit the effects of GH |
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Term
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Definition
synthetic GHRH mimic: used in Replacement THERAPY DIAGNOSIS OF PITUITARY FUNCTION AUGMENT GH production: If someone is able to produce GH but not able to release it, it is possible to administer GHRH and allow the body to secrete more GH than what it would normally do on its own Advantage: This keeps the negative feedback functioning. Because if the levels get too high, whatever GHRH we administer is NOT going to release anymore GH due to the negative feedback
Disadvantage: the amounts that are released endogenously may NOT be SUFFICIENT for CHILDREN They need higher doses than what the body can produce on its own
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Term
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Definition
"an insulin-like growth factor" Rx: to help children to grow and reduce the effects of the lack of GH. à If the patient is using the human GH and the effects of it start to wane after time, then it’s probably due to the GH antibodiesà and so the patient can be switched to IGF-1 to mimic the effects
à all of those effects of GH are shared by IGF-1 à it has the ability to activate insulin receptors, which can result in è HYPOGLYCEMIA |
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Term
| Effects of Excess Growth Hormones |
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Definition
*Usuaully due to benign Pituitary Tumor which results in an increase release of substance Effects: Children: Gigantism Adults: Acromegaly (enalrgement of facce, hands, feet) Associated with HTN, glucose intolerance, lethargy, sleep apnea inc morbidity due to CVD, upper airway obstruction
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Term
Treatment of Excessive Growth Hormone Goals and treatment Options |
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Definition
Goal: Reduce GH secretion from Pituitary and its effects |
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Term
| Somatostatin Receptor Agonist |
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Definition
*when somatostatin receptor is activated, it inhibit the release of GH from the pituitary There are 5 subtypes: |
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Term
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Definition
Sandostatin : somatostatin receptor agonist
Selective for Subtype 5 and 2 aslo little activity on type 3,1,4 ADR: Abdominal PAin Gall stones malabsorption of fat reduce glucose tolerance
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Term
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Definition
Pegvisomant- "Growth Hormone Receptor Antagonist" - Its a large protein so will develop antibodies agst it
- so usually a second line therapy for somatostatin non-responders
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