Pituitary Hormones

  1. What are possible solutions/treatments for hypersecretion of an endocrine gland?
    • Removal of tissue by surgery, irradiation followed with replacement therapy
    • Administration of drugs./hormones that suppress synthesis and secretion of the hormone
  2. What are the 3 chemical classes of hormones?
    • Steroids: adrenal, sex, claciferols, vitamins
    • Peptides/proteins: hypothalamic releasing factors, pituitary hormoines, insulin/glucagon/calcitonin/oxytocin/vasopressin/relaxin/GI hormones
    • Amines: dopamine, epi, thyroid hormones
  3. What is the administration route for the differet types of hormones?
    • Parenterally: peptide and catecholamens
    • Oral: synthetic steroids and thyroid hormones
  4. What is the system of simple negative feedback control?
    • ´╗┐´╗┐Hormone secreted from endocrine gland
    • Hormone travels to target cell via blood
    • Substrate released
    • Increased level of substrate in blood inhibits release of hormone from endocrine gland
  5. What are examples of simple negative feeback control?
    • glucagon/glucose
    • PTH/plasma clacium
    • aldosterione/plasma sodium
    • insulin/glucose
  6. What are examples of complex endocrine control system?
    • TRH/TSH/thyroxine
    • CRH/ACTH/glucocorticoids
    • GnRH/LH & FH/estrogen & progesterone
  7. What are the effects of GH on normal tissue?
    • Positive nitrogen balance
    • Protein synthesis enhanced
    • Electrolyte retention
    • AA transport into tissues
  8. What are the effects of GH in DM?
    Hyperglycemia and ketosis
  9. What is Somatomedin C?
    • Insulin-like Growth Factor 1
    • Stimulated by GH to stimulate chondrocytes to form cartilage and matrix
  10. How is GH release regulated?
    GHRH (positive effect) or somatostatin/SST (negative effect) released from neurons in hypothalamus
  11. What is the signal pathway of GHRH in the pituitary?
    • Receptor
    • Gs (stimulatory) transducer
    • Increase Adenylyl Cyclase
    • Increase cAMP
    • Activate protein kinase A
    • Phosphorylation of proteins
  12. What is the signal pathway of SST in the pituitary?
    • Receptor
    • 1. Gi (inhibitory) transducer
    • Decrease Adenylyl Cyclase
    • Inhibit GH relase
    • 2. Go (inhibitory) transducer
    • Inhibit Ca2+ channels
    • Inhibit GH release
  13. What are factors the stimulate GH release?
    • Hypoglycemai
    • Oral/IV AAs
    • Deep sleep
    • Exercise
    • Dopamine Agonists
  14. What is Sermorelin?
    Synthetic GHRH for treatment of hypopituitary dwarfism from GHRH deficiency at hypothalamic level
  15. What is Mecasermin?
    • Synthetic IGF-1 protein that binds to and increases t1/2 of human IGF-1
    • Used in Laron Syndrome with defective GH receptors
  16. What is the treatment of Hypopituitary Dwarfism?
    • GH SQ/IM thoughout childhood
    • Dex hormones at puberty
  17. What's the effect of glucocorticoids on GH?
    Decrease GH release
  18. What's the treatment of Hyperpituitary Dwarfism?
    • Defective GH receptros can't stimulate IGF-1
    • Mescasermin therapy increases IGF-1 t1/2
  19. What's the risk brough by use of GH for cosmetic purposes?
    Carpal Tunnel Syndrome
  20. What's bromocriptine?
    • Dopamine agonist
    • Paradoxocal inhibition of GH release in pts with Acromegally
    • Best in pts with GH & Prolacitn adenoma
  21. What's Octreotide?
    • SST synthetic analog with longer t1/2
    • IM once a month for Acromegally
    • SE: nausea, diarrhea, abdominal pain
    • Pancreatic cholera (inhibits VIP secretion)
  22. What's Pegvisomant?
    • GH antagonist
    • Binds to GH receptors to decrease IGF-1 production
    • SQ daily
    • SE: site reactions, nausea, diarrhea, chaest pain, flu syndrome
  23. What regulates Prolactin release?
    • Dopamine from hypothalamus (Inhibits synthesis and release)
    • TRH (enhncaese prolactin release via Ca2+ mobilization)
  24. What factors stimulate prolactin secretion?
    Preganancy (sucking, stress, hypoglycemia, estrogen)
  25. What's the treatment for hyperprolactinemia?
    • Bromocriptine (dopamine agonist)
    • S/S: galactorreha, amenorrhea, vision impairment
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Pituitary Hormones