Biochemistry Flashcards
what is the pancreas made up of?
Islets of Langerhans
what cell types make up the islets of Langerhans?
alpha cells
beta cells
delta cells
PP cells
what do alpha cells of the pancreas secrete?
glucagon
what do beta cells of the pancreas secrete?
insulin
what do delta cells of the pancreas secrete?
somatostatin
what do PP cells of the pancreas secrete?
polypeptide
what is formed when insulin is cleaved?
two polypeptide chains linked by disulphide bonds with a connecting C peptide as a by-product
what blood glucose stimulates beta cells to release insulin?
above 5nM
what happens in diabetes to sensing of blood glucose?
beta cells lose their ability to sense due to hyperglycaemia taking it outside the KM of glucose
what does the KATP channel consist of?
inward rectifier subunit (Kir6) sulfonylurea receptor (SUR1)
what does a Kir6 mutation cause?
neonatal diabetes
management of neonatal diabetes
SUs
management of congenital hyperinsulinism
diazoxide (K+ channel activator)
what is MODY?
maturity-onset diabetes of the young
what mutations can cause MODY?
glucokinase (MODY2)
HNF transcription factors (MODY1/3)
two genetic conditions that cause insulin resistance
- Leprechaunism (Donohue syndrome)
- Rabson Mendenhall syndrome
both have AR mutation of insulin receptor
what receptor type does insulin bind to?
receptor tyrosine kinase
what receptor type does GH bind to?
cytokine receptor
what receptor type does calcium bind to?
GPCR
what happens if pyruvate/oxaloacetate is limited?
acetyl-CoA is converted to ketones
what does having low/no insulin result in?
reduces the amount of glucose being taken up by tissues from the blood, so fatty acids are oxidised for energy
what does accumulation of ketone bodies cause?
acidosis
what does high glucose excretion cause?
dehydration
acidosis
coma and death
presentation of DKA
vomiting
dehydration
increased HR
distinctive smell on breath
