Biochemistry Flashcards
What is the “normal” fasting blood glucose
4-6mM
What is the fasting blood glucose level that indicates hypoglycaemia?
- <4mM
What is the fasting blood glucose level that indicates pre-diabetes?
- 6-7mM
Insulin is described as a _____ hormone
- peptide hormone
What cell within the pancreas produces insulin?
- beta-cells
What is unique about beta-cells?
- they have a glucose sensing ability
Where is insulin produced within the beta cells?
- rough endoplasmic reticulum
Proinsulin is cleaved by what?
- ca2+ dependant endopeptidases
What is proinsulin cleaved into?
- insulin
- c-peptide
What are the 4 different cell types found in the islets of langerhans?
- beta cells
- alpha cells
- delta cells
- PP cells
What do alpha cells secrete?
- glucagon
Name a short acting insulin supplement?
- lispro
Name a long acting insulin supplement?
- glargine
How is insulin secreted?
- glucose enters b-cell by GLUT2 transporters
- glucose is cleaved by glucokinase and enters glycolysis, TCA and oxidative phosphorylation
- increase in ATP
- ATP dependant K+ channels close
- depolarisation
- opening of Ca2+ dependant channels
- release of insulin from granules
How many ATP molecules are produced per glucose molecule?
- 36
What does biphasic release of insulin mean?
- 1st phase - prevents a sharp increase in blood glucose post ingestion
- 2nd phase - more tuned to insulin requirement
Why might T2DM have hyperinsulinemia?
- increased insulin release due to downregulation and insulin resistance
What is the FBG range for gestational diabetes?
- FBD>5.5mM
MODY is described as what?
- defective glucose sensing and loss of insulin secretion
MODY has mutations in what?
- TF 1
- TF 3
(Transcription factor)
What drug is used in MODY?
- Sulphonylurea
Sulphonylureas_____
- inhibit the potassium channel
- increased release of insulin
Diazoxide____
- inhibits insulin secetion
- opens potassium channel
Other than regulating blood glucose levels what else is insulin involved in?
- DNA synthesis
- protein synthesis
- growth response
Define insulin resistance?
- higher levels of insulin than normal is required to produce an action
Donohue syndrome___
- autosomal recessive
- mutations in gene for the insulin receptor
Symptoms of diabetic ketoacidosis?
- vomiting
- dehydration
- increased HR
- ketone smell from breath
Insulin normally inhibits____
- lipolysis
