Pancreatic hormones Flashcards
What do the exocrine cells in the ACINI produce?
digestive enzymes
Endocrine cells in the pancreatic islets produce?
Pancreatic hormones
What do beta cells produce?
Insulin
What do Alpha cells produce?
Glucagon
What do delta cells produce?
somatostatin
What do F cells produce?
Pancreatic polypeptide
Describe insulin
51aa polypeptide hormone two chains : a & b joined by a disulphide bond MW ~6000kDa synthesised as PREPROINSULIN insulin stored in beta cell secretor granules complexed with zinc
Insulin action in the muscle:
increase glucose transporter (GLUT4)
Increase glycogen synthesis
Insulin action in liver:
Increase glycogen synthesis
Increase lipogenesis
Decrease gluconeogenesis
Insulin action in adipose tissue:
Increase glucose transporter (GLUT4)
Increase lipogenesis
Decrease lipolysis
What is the transporter in liver?
GLUT2
Synthesis and release of insulin is stimulate by increased serum concentrations of:
Glucose
Amino acids
Free fat acids
Ketoacids
What is the neural regulator of insulin secretion?
increased parasympathetic activity in response to food in the digestive tract. Stimulate insulin release.
Sympathetic stimulation and adrenaline inhibit?
insulin secretion
Stress or excersice increase blood glucose levels by?
decreasing insulin secretion
Glucagon is synthesised where and as what?
alpha cells
as PREPROGLUCAGON
What is glucagon?
29aa peptide
why does glucagon oppose the actions of insulin?
it acts to mobilise fuels
what are the stimulators of glucagon secretion?
low blood glucose
decreased plasma levels of free fatty acids
prolonged fasting or sustained exercise
what are inhibitors of glucagon secretion?
high blood glucose
increased levels of plasma free fatty acids
insulin
fed state
what is type 1/ Diabetes mellitus?
damage to pancreatic beta cells, resulting in lack of insulin\autoimmune damage
juvenile onset
treated by insulin replacement therapy
What is type 2 diabetes?
loss of tissue responsiveness to insulin
usually adult onset
less severe but more common
TREATMENT: weigh loss, dietary change and exercise
drug therapy aimed at cell sensitivity to insulin, enhancement
What is the drug used for diabetes type 2 and how does it work?
METFORMIN
enhances insulin sensitivity by increasing insulin receptor tyrosine kinase activity
enhances glycogen synthesis
increases recruitment and transport of GLUT4 transporters to plasma membrane
Symptoms of diabetes
High blood glucose
glucose in uirine
increased urine volume - osmotic diuresis
increased thirst
what happens if diabetes type 1 is untreated?
Increased mobilisation and oxidation of fats metabolic acidosis increased protein catabolism tissue damage dehydration cereal oedema
What are the symptoms of excessive insulin?
low blood glucose: affects CNS blurring of speech, vision unsteadiness unconsciousness Increased sympathetic nervous activity raised adrenaline increased heart rate sweating gluconeogenesis in liver raised blood glucose
What is the name for congenital insulin resistance?
Leprachaunism
Describe leprachaunism
lack of functional receptors
severe intrauterine growth retardation
infants usually die within 12 months
