Lec 18 antihyperglycemics Flashcards
What secretes insulin?
beta cells
What secretes islet amyloid peptide [amylin]?
beta cells of pancrea
What is function of amylin [islet amyloid peptide]?
modulates app
What secretes glucagon?
alpha cells
What is action of glucagon?
mobilizes glycogen stores and turns on gluconeogenesis
What secretes somatostatin?
delta cells of pancreas
What is action of somatostatin?
inhibits secretion of other pancreatic and GI hormones
What secretes pancreatic peptide?
F cells [PP cells] of pancrea
What is action of pancreatic peptide?
facilitates digestive processes produced by F cells
What is preferred treatment for gestational diabetes?
insulin
How is insulin synthesized?
from preproinsulin –> proinsulin processed in golgi apparatus –> packaged to granules and cleaved to insulin and peptide C
What is mech of insulin secretion?
if high gluc concentration –> enter by GLUT2 –> ATP production increases –> K channels close and depolarize cell –> Ca channels open and Ca enters –> increase insulin secretion
How is insulin degraded?
60% by liver
35-40% by kideny
What type of receptor is insulin receptor?
tyrosine kinase
Where is GLUT1? function?
all tissues esp RBCs, brain
- basal uptake of glucose; transports across BBB
Where is GLUT2? function?
beta cells of pancreas, liver, kidney, gut
- regulation of insulin release and other aspects of glucose homeostasis
Where is GLUT3? function?
brain, placenta
- uptake into neurons, other tissues
Where is GLUT4? function?
muscle, adipose
- insulin-mediated uptake of glucose
Where is GLUT5? function?
gut, kidney
- absorption of fructose
What are effects of insulin on liver?
- inhibit glycogenolysis, convert fatty acids and AA to keto acids; convert AA to glucose
- promote glucose storage as glycogen
- increase TG synthesis and VLDL fomation
What are the effects of insulin on muscle?
- increase protein synthesis
- increase glycogen synthesis
What are effects of insulin on adipose tissue?
increase TG storage
What is incretin effect?
increased release of insulin in response to oral glucose admin vs IV admin b/c of release of GI peptide hormones [incretins] from GI endocrine cells which increase insulin release = GLP1 and GIP
What is DDP?
DDP = dipeptidyl peptidase; metabolizes GLP-1 therefore less insulin release in response to oral glucose
