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Somatostatin

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Somatostatin, Somatotropin Release Inhibiting Factor, Growth Hormone Release Inhibiting Factor, Somatostatinoma

  • Physiology
  1. General
    1. Somatostatin is a 14-Amino Acid peptide
    2. Cyclic tetradecapeptide
  2. Hypothalamic Somatostatin
    1. Secreted by the Hypothalamus median eminence
    2. CNS effects
      1. Decreased Growth Hormone secretion
      2. Decreased Thyroid Simulating Hormone secretion
      3. Decreased Prolactin secretion
  3. Pancreatic Somatostatin
    1. Secreted by pancreatic delta islet cells
      1. Triggered by increased Blood Glucose and Amino Acid concentrations
    2. Inhibits Insulin and Glucagon secretion, as well as pancreatic exocrine enzyme secretion
    3. Decreases gastric acid secretion by direct action at parietal cells
      1. Also suppresses Gastrin and histamine release, which result in decreased acid secretion
    4. Inhibits intestinal absorption of Glucose and Triglyceride
    5. Decreases gastric emptying and peristalsis
    6. Inhibits renin secretion from Kidney
  • Pathophysiology
  • Somatostatinoma
  1. Somatostatinoma is a rare Somatostatin-Secreting tumor derived from pancreatic delta cells
  2. Findings
    1. Diabetes Mellitus
    2. Malabsorption with steatorrhea
    3. Cholelithiasis
    4. Hyperchlorhydria
    5. Weight loss
  • Preparations
  • Synthetic Somatostatins
  1. Octreotide (Sandostatin)
    1. Synthetic cyclic octapeptide with activity similar to Somatostatin
    2. Indicated in Bleeding Esophageal Varices, Sulfonylurea Toxicity and several endocrine conditions
  • References
  1. Goldberg (2014) Clinical Physiology, Medmasters, Miami, p. 120-46