Pancreatic Hormones Flashcards
Beta cells, alpha cells, and delta cells secrete _
Insulin
Glucagon
Somatostatin
What is the significance of the portal system connecting the liver and pancreas?
Hormones from the pancreas reach the liver in very high concentrations
Insulin is secreted directly into the blood. What are the precursors? What else is contained in the insulin secretory granules
Pre-pro
Pro-
insulin + C peptide
Insulin is composed of 2 AA chain joined by _ bonds
Disulfide
Maximal insulin effects require binding to 90% of available insulin receptors. true or false?
False. Only 10% binding required
The insulin receptor is a tetramer. What subunit and domain binds insulin? What is transmembrane?
Alpha - cysteine rich domain
Beta
Insulin receptor activation leads to increased conversion of glucose to glycogen. What is the only glucose transporter that is responsive to insulin?
GLUT 4 - upregulated following receptor activation
The 2 immediate results of insulin receptor activation are _
Increase glucose transport into cell
Increase AA and ion influx for protein synthesis
What are the effects of insulin on liver phosphorylase and liker glucokinase?
Inhibits phosphorylase (breaks down glycogen) Promotes glucokinase (traps glucose)
Brain cells depend on insulin for glucose up take. True or false?
False. Brain cells are glucose permeable without insulin i.e. they don’t need Glut4
The major function of insulin is to use up glucose as only energy source, while blocking use of fats or glycogen.
Just know this
Type 1 diabetics have elevated levels of plasma cholesterol and FAs. WHy?
Because the absence of insulin promotes hepatic breakdown of free FAs to phospholipids and cholesterol
Ketoacidosis occurs in diabetics because _
Excess acetoacetic acid is formed from liver
How does insulin interact with GH?
Synergizes to promote growth
In beta cells, glucose enters via _. How does this affect ADP levels? What does this accomplish?
GLut2
Increased ADP / reduced ATP
Closing ATP sensitive ion channels
Depolarization, Ca++ influx, Insulin release
The major effects of glucagon are _ (2)
Increased glycogenolysis
Increased gluconeogenesis
Glucagon increases insulin release. True or false? What hormone depresses both glucagon and insulin release?
True
Somatostatin
Type 1 diabetes can be caused by viral infection. true or false?
True. Hereditary suceptibility to beta-cell destruction
What is metabolic syndrome?
obesity, insulin resistance, hypertension, hyperglycemia and elevated plasma lipid, all precursor for diabetes and cardiovascular disease
Thyroid hormone and Cortisol are hunger (promoting / depressing)
Promoting
Leptin, Insulin, CRH are hunger (promoting / depressing)
Depressing
A proposed link between obesity and diabetes is that in the obese state, there is increased expression of _ in the mitochondria
Uncoupling protein 2
Hyperinsulinism is characterized by shock due to too low insulin levels. This can be treated by _
Surgery
Diazoxide (reduces insulin release)
