Formation and degeneration of pancreatic beta cells Flashcards
islets are clusters of approx 1000 _____ cells
endocrine
approx how many islets are in a human pancreas
1 million
what does the exocrine pancreas secrete (acini and ducts)
secrete digestive enzymes
alpha cell secrete what
glucagon
beta cells secrete what
insulin
delta cell secrete what
somatostatin
PP cells secrete what
pancreatic polypeptide
epsilon cells secrete what
ghrelin
insulin is cleaved from what
pro insulin and c peptide
glucose sensing in beta cells facilitates what
dose dependant stimulation of insulin secretion by glucose
what are essential molecular components of beta cell glucose sensing
glucose transporters (GLUT1/2)
Glucokinase (GCK)
oxidative metabolism
Katp channels (Katp)
L-type voltage dependant (ca2+) channels (VDCC)
exocytotic machinery
pancreatic islets are composed of how many principle endocrine cell types
3
what are the three principle endocrine cell types in the pancreatic islets
alpha
beta
delta
beta cells produce what
pro insulin
beta cells produce proinsulin which is packaged and processed in large dense vesicles called what
insulin granules
insulin is secreted in response to what
glucose stimulation
insulin drives what
anabolic pathways in target tissue
insulin drives anabolic pathways in target tissues to promote what
storage of nutrients and low blood glucose
what is the formation of beta cells called
neogenesis
what is neogenesis
formation of new beta cells
what is Neurogenin3
a transcription factor
what is the “master regulator” of pancreatic development
PDX1
what does neurogenin3 do
transcription factor that drives endocrine cell lineage
what are key beta cell identity transcription factors
PDX1
MAFA
NKX6.1
PAX6
what is beta cell neogenesis
formation of new beta cells from ductal progenitors during development
how is this term classified
formation of new beta cells from ductal progenitors during development
beta cell neogenesis
in extreme beta cell loss, what cells can differentiate into insulin expressing cells in mice
alpha and delta cells
lineage tracing in possible in mice but not in …
humans
why is lineage tracing possible in mice and not in humans
mice do not express human diptheria toxin receptor (DTR)
tissues are resistant dipetheria toxin (DT)
expression of DTR in beta cells enable what
selective ablation of beta cells by DT
following beta cell ablation, what cells switch on insulin production
alpha cells
