Postpranial Glucose Metabolism Flashcards
How much of the pancreas is for endocrine function?
1-2 %, from the islets of Langerhans
What are the major exocrine products of the pancreas?
bicarbonate, amylase, trypsin, chymotrypsin, carboxypeptidase
What are the four types of cells in islets of Langerhans
beta-cells for insulin/amylin
alpha-cells for glucagon
delta-cells for somatostatin
theta (phi)-cells for pancreatic polypeptide
Insulin preprohormone is cut into peptides by _____?
endopeptidase
prohormone converter 2 - between pre and pro
prohormone converter 1 between pro and insulin
T/F Insulin gene has a lot of mutations associated during evolution
False, the gene is highly conserved
What are the two distinct phases of insulin secretion?
1st sharpe rise in secretion
2nd prolonged secretion phase
Describe the cellular event leading to insulin secertion
Glut 2 channel allowing glucose entry, leading to production of ATP and shuts ATP-gated K+ channels, allowing the opening of Ca2+ channels, and downstream enzymic action
T/F amino acids trigger the insulin pathway in similar fashion as glucose
True, except amino acids directly enter the TCA cycle
T/F More insulin gets released when glucose is administered intravenously
False, more is released with oral intake of glucose
Where is incretin secreted? What is the trigger of its release?
in the gut
triggered by nutrients: glucose, fatty acids, amino acids
T/F Proglucagon gives rise to glucagon is the gut
False, it gives rise to glucagon in the pancreas, an GLP-1 in the gut
Where is glucagon-like peptide secreted?
form the L-cells of small intestine
What is the function of GLP?
binding to beta cells to stimulate proinsulin production
also blocks gastric emptying
inhibit glucagon secretion
promote beta-cell growth
GLP has great therapeutic use for diabetes. Why isn’t it used?
It has a very short half life
What is Exenatide?
it’s a GLP-1 mimetic for treating diabetes
