GIT Pharm – Misc

Master answer

Pancreatic Secretion

Exocrine Secretions

• produced by acinar and ductal cells
• ~1.5L per day
• HCO₃^–
  • alkalinize gastric contents
  • enzyme carbonic anhydrase
• Water
• Enzymes
  • Proteases: Trypsinogen → Trypsin (by enterokinase in gut), Chymotrypsinogen → Chymotrypsin. Proteolysis.
  • Amylase: Hydrolysis of glycogen, starch, and complex carbohydrate.
  • Lipase: Hydrolysis of dietary triglycerides.
  • Others: ribonuclease, deoxyribonuclease, gelatinase and elastase

Endocrine Secretions

• Insulin
  • polypeptide hormone
  • synthesized from proinsulin in RER of B cells in Islets of Langerhans
  • Excreted via exocytosis in response to ↑intracellulae Ca²⁺
  • Minimal protein binding, tiny Vd 0.075 L/kg
  • Metabolized in liver, muscle, kidney byt Glutathione insulin transhydrogenase
  • Renal elimination of inactive metabolites
  • Circulatory hald life ~5mins
  • Increased anabolism, decreased catabolism
  • maintains normal blood glucose levels by facilitating cellular glucose uptake, regulating carbohydrate, lipid and protein metabolism
  • promotes cell division and growth through its mitogenic effects
• Glucagon
  • polypeptide hormone
  • synthesized in pancreatic A cells
  • secreted into portal vein
  • Circulating half life ~5mins
  • Metabolized in liver (1st pass) – low circulating level
  • Glycogenolysis, gluconeogenesis, glucose release, ketone formation
  • Lipolysis
  • Inotopy, increases metabolic rate
  • Stimulates somatostatin, insulin release
• Somatostatin
  • polypeptide hormone
  • Inhibits Glucagon, Insulin, other pancreatic peptides
  • may function as CNS neurotransmitter

Pharmacology of Octreotide