Insulin Flashcards
Islets of Langerhans
Cell clusters alpha, beta, delta and P cells within the pancreas, that secretes hormones.
Hyperglycemia
A condition of excess glucose circulation in the plasma
SGLT1
This is responsible for glucose absorption in the small intestine, reabsorbing 3% of filtered glucose in the renal proximal tubule
SLT2
Responsible for reabsorption in the small intestines proximal tubule, reabsorbing 90%
cAMP
Cyclic Adenosine Monophosphate is a second messenger used for intracellular signal transduction
Protein Kinase A
A family on enzmyes with activity dependent on cellular levles of cAMP
Insulin
A pancreatic hormone that regulates blood glucose levles by stimulating the conversion of glucose to glycogen.
Insulin Receptor
A tyrosine kinase receptor that activates on insulin binding, phosphorylating itself and other proteins.
Negative Co-operativity
Insulin binding at one sites decreases insulin binding affinity in the other site.
Insulin Receptor Substrate Family
A family of proteins phosphorylated by activated insulin receptor, with roles in insulin-stimulated signal transduction pathways.
P13K
Phosphoinositide-3 Kinase Heterodimers are lipid kinases, regulating various processes.
PDK1
Pyruvate Dehydrogenase Kinase is a major regulator of P13K pathways transmission to downstream kinases.
AKT1
An enzyme responsible for regulation of glucose uptake, mediating insulin induced translocation of GLUT4 to the cell surface.
What is the structure of Insulin?
A 51 residue anabolic protein secreted by beta cells in the Islets of Langerhans, containing two A/B chains connected by disulfide bonds.
GLUT4
A transporter for glucose in insulin-dependent mechanisms
What is the mature, functional insulin hormone a product of?
Proinsulin
Proinsulin
An insulin precursor, giving rise to the double chained insulin, by removal of the C-peptide
What is Diabetes mainly caused by?
Mutations in the insulin gene, being associated with impaired folding of proinsulin, leading to ER stress, beta cell death and diabetes.
What is diabetes characterised by?
Decreased glucose tolerance resulting from a relative deficiency of insulin or lack of sensititiy to insulin, with resulting hyperglycemia.
What are the associated problems of hyperglycemia?
Long term exposure of tissues to elevated glucose concentrations involving development of macro-microvascular disease, like coronary heary disease.