Hormones of pancreas

• What are the important values of blood glucose concentrations?

  Post-absorptive: 4.5-5.5 mmol/L

  Post prandial: 6.5-7.2 mmol/L

  Fasting: 3.3-3.9 mmol/L
• What are the role of the two major hormones in the pancreas?

  Insulin: Facilitates glucose uptake & storage of glucose in liver & muscle cells

  Glucagon: Faciliates breakdown of glycogen (primarily in the liver) & synthesis of glucose
• What are the sources of blood glucose?

  Diet-Intestine & liver (Galactose & fructose)

  Liver-Glycogenolysis & gluconeogenesis

  Muscle-Amino acids

  Liver & muscle-Lactic acid, glycerol & glucogenic compounds
• What are the hormones that regulate blood glucose?

  Glucokinase, insulin, glucagon

  GLP-1, GIP, epinephrine, cortisol, growth hormone
• What are the effects of glucagon?

  -Stimulate breakdown of stored liver glycogen

  -Promotes hepatic gluconeogenesis

  -Promotes hepatic ketogenesis
• What are the effects of insulin?

  -Facilitates glucose metabolism & storage

  -Promotes glucose uptake by cells

  -Promotes protein & fat synthesis

  -Promotes use of glucose as an energy source
• What are the effects of amylin?

  -Suppresses postprandial glucagon secretion

  -Slows gastric emptying

  -Reduces food intake & body weight
• What are the effects of GLP-1?

  -L-cells secrete them (located in the gut)

  -Enhances glucose-dependent insulin secretion

  -Suppresses postprandial glucagon secretion

  -Slows gastric emptying

  -Reduces food intake & body weight

  -Promotes cell health
• What is the significance of incretin effect?

  It stimulates production of insulin to reduce increase in blood glucose
• Review the regulation of blood glucose

  Pathways

  
• What are the actions of insulin?

  -Increase glucose uptake by increasing expresssion & exocytosis of GLUT 4 receptors

  -Decrease proteolysis & ketogenesis by inhibiting catabolic activities

  -Increases glycogen, lipid & protein synthesis by promoting anabolic response

  -Decreases lipolysis by decreasing mobilization of fat from adipose tissue

  -Increases glycolsis & ion uptake by increasing K+ uptake

  -Decreases gluconeogenesis & glucogenolysis
• What are the actions of glucagon?

  -Increases gluconeogenesis by increasing synthesis of glucose

  -Decreases glycogen synthesis by inhibits glycogen synthase by phospharylation

  -Increases glycogen, lipid & protein breakdown

  -Decreases lipogenesis by inhibiting fatty acid synthase

  -Increases lipolysis, B-oxidation & ketone bodies by increasing mobilization of fat

  -Decreases protein synthesis by mobilizing aminio acids
• What is euglycemia?

  Balance between glucose utilization & glucose production
• What is hyperglycemia & hypoglycemia?

  Hyperglycemia is an abnormality in blood sugar stability (Increases).

  Hypoglycemia is an abnormality in blood sugar stability (Decreases).
• What are the characteristics of hyperglycemia?

  -Islet dysfunction & peripheral insulin resistance
• What are the types of hyperglycemia?

  -Type I DM

  -Type II DM

  -Impaired DM

  -Gestational DM

  -Basal: Normal absorption & increased production

  -Postprandial: Abnormal production & absorption
• What are the characteristics for diagnosing postprandial hyperglycemia?

  -Determined by timing, quantity & composition of meal

  -OGTT is a ref test

  Diagnosis

  • Fasting plasma glucose concentration is consistenly >7mmol/L
  • 2 hr plasma glucose concetration is consistenly >11 mmol/L
  • HbA1c is >6.5 mmol/L
• What are the benefits of HbA1c test?

  -Cheap

  -Reliable

  -Convenient
• What are the symptoms of hyperglycemia?

  -Polyuria

  -Polydipsia

  -Weight loss

  -Polyphagia

  -Glycosuria
• What are the secondary causes of hyperglycemia?

  -Destruction of pancreas due to chronic pancreatitis

  -Endocrine disorders like Cushing Syndrome, acromegaly & pheochromocytoma

  -Drug usage such as glucocorticoids, pheytoin & estrogens

  -Gestational diabetes (decreased insulin sensitivity)

  -Total parental nutrition & dextrose infusion
• What are the complications of hyprglycemia?

  -Metabolic disorders: Obesity & activation of oxidative stress

  -Vascular damage: Microvascular (Retinopathy, Nephropathy & Neuropathy) & Macrovascular (Brain, Heart & Extremities)
• What are the characteristics of hypoglycemia?

  -Insulin production decreases

  -Epinephrine & glucagon production increases

  -Growth hormone increases

  -Cortisol production increases
• What are the symptoms of hypoglycemia?

  Neuroglycemic:

  • Headache
  • Confusion
  • Slurred speech
  • Seizure
  • Coma
  • Death

  Adrenergic:

  • Anxiety
  • Palpitation
  • Tremor
  • Sweating
• What type of cells secrete glucagon?

  Alpha cells in pancreas
• What does glucagon stimulate?

  Hypoglycemia
• What does glucagon inhibit?

  Hyperglycemia, insulin & somatostatin
• What type of cells secretes insulin?

  Beta cells from the pancreas
• What does insulin stimulate?

  Hyperglycemia

  
• What does insulin inhibit?

  Alpha-2 adrenergic receptor agonism
• What does the delta cells in the pancreas secrete?

  Somatostatin
• What is the function of somatostatin?

  Regulates insulin & glucagon in the body
• What does somatostatin stimulate & inhibit?

  Stimulates gastric acid & inhibits vagus nerve
• What does the epsilon cells in the pancreas secrete?

  Ghrelin
• How does ghrelin work?

  Stimulates appetite & hunger from the lateral hypothalamus & promotes release of growth hormones from anterior pituitary
• What does ghrelin stimulate & inhbit?

  Stimulates fasting, sleep deprivation & inhibits intake of food
• How are the pancreatic polypeptide secreted?

  From the gamma cells of the pancreas (PP cells)
• What is the role of pancreatic polypeptide?

  Increases gastric secretion & promotes satiety
• What are the stimulatory & inhibitory effects of pancreatic polypetide?

  Stimulates fasting & inhibits food intake