Endocrine Pancreas Flashcards
Cells of Islets Langerhans communicate with each other> How?
Gap junctions-rapid cell to cell communication between a-a, b-b, a-b
What is the direction of blood flow in Islets of Langerhans?
From center to periphery
Paracrine actions of Islets of Langerhans work __ _______ of blood flow.
in reverse
Insulin is a peptide hormone-two chains connected by ______ brigdes.
Didulfide
Steps in insulin formation
Preproinsulin–>Proinsulin–>Insulin+C peptide
Proinsuline
No signaling peptide
C peptide still attached to insulin
Packaged into secretory granules
Proteases in the granule cleave proinsulin
Insulin and cleaved C peptide packaged together in _______ _________ .
Secretory vesicles
Insulin and C peptide are secreted in ______ quantities into blood.
Equimolar
_ _________ can be used as a marker of endogenous insulin secretion.
C peptide
Where is C peptide typically secreted?
In urine
How many phases of Insulin release are there?
Two (it is biphasic)
Which phase of insulin secretion is lost first in diabetic individuals?
1st
What are other modulators of insulin secretion?
CCK (stimulates via Gq)
Somatostatin (Inhibits via Gi)
Ach (stimulates via Gq)
GIP (stimulates)
T/F: Insulin downregulates its own receptor.
True
What is an alternative intracellular pathway for glucose uptake INDEPENDENT of insulin.
AMP-kinase results in GLUT4 translocation to plasma membrane.
