Insulin and glucose regulation Flashcards
What are the four types of cells found in the pancreas?
Beta cells, alpha cells, delta cells and PP cells
What do delta cells secrete?
Somatosatin
What do PP cells secrete?
Pancreatic polypeptides
What is the endocrine function of the pancreas?
To produce hormones and transport secreted hormones to the portal vein
What is insulin initially produced as?
Proinsulin
What are the three domains of proinsulin?
aminoterminal β-chain, carboxyterminal α-chain and
the connecting inactive C-peptide.
What kind of bond holds the proinsulin together?
disulphide
What is the half life of insulin?
5-8 minutes, it is then metabolised in the liver and kidney
What mineral causes insulin secretion?
influx of calcium causes a release of insulin via exocytosis
What is the name of the protein that transports glucose?
GLUT
What is the first phase of the biphase response?
pre-formed insulin is released (this is very quick)
What is the second phase of biphase?
The more prolonged phase due to the synthesis of new insulin
What hormone produced in the GIT secretes insulin?
GIP
What does an increase in amino acids lead to?
An increase in insulin and therefore an increase in protein synthesis
What are that target cells for glucose storage?
hepatocytes, myocytes and adipocytes
Why does insulin increase uptake of amino acids
Hepatic gluconeogenesis requires amino acids
What is the primary organ of glucagon?
The liver, it metabolises glucose from hepatic glycogen and gluconeogenesis
Where is glucagon metabolised?
In the liver and the kidney, it has a half life of 5-6 minutes
What is the correlation between increased levels of AA and glucagon
it increases the levels of glucagon
What is the anticipatory release of GIP?
Insulin resposne is greater when glucose is ingested orally as there is an anticipatory release of GIP when it knows that food is going to be ingested
What is the effect of glucagon on protein metabolism?
Increases the levels of protein degredation into amino acids (which are needed for gluconeogenesis)
What is GLUT-4 and where is it found primarily?
insulin-regulated glucose transporter and it is found primarily in adipose tissue and striated muscle
What is glucose nadir?
The lowest levels of glucose during a days set point/ the glucose baseline
How does GIP work?
after eating, GIP travels through the circulation to the beta cells to increase the release of insulin
