Pancreatic Hormones Flashcards
what do alpha cells secrete
glucagon, proglucacon
what do beta cells secrete
insulin C peptide proinsulin islet amyloid polypeptide GABA
what do delta cells secrete
somatostatin
what do episolin cells secrete
ghrelin
what do PP or F cells secrete
pancreatic polypeptide
steps on insulin secretion
Insulin gene translated to preproinsulin in ER, preproinsulin cleaved immediately. Proinsulin packaged into granules in Golgi. Proinsulin converted to insulin and C-peptide in secretory vesicles.
half life of insuline
3-5 minutes
how does glucose affect insulin
most potent stimulator of release
increass intracellular ATP, inhibits K channel, results in Ca++ inflex
how does vagal stimulation affect insulin
acetylcholine activate M3 receptos and increass intracellular Ca
how do hormones affect insulin
GLP1 amplifies insulin release
somatostatin inhibits insulin releasess
how do catecholamines affect insulin
beta adrenergic stim (epinephrine) can amplify secretion
how does alpha adrennergic stimulation affect insuline
inhibit insulin release
Describe the cellular events that take place during glucose and acetylcholine stimulated insulin secretion.
Glucose moves down conc. gradient into cell (likely thru glucose transporter 2), leads to increased ATP in cell. This inhibits K channel, memb depolarizes, and Ca flows in and is involved in insulin release.
cellular consequences that occur following activation of the insulin receptor.
activates intracellular signaling pathways. Outcomes are mitogenic (cellular growth), and metabolic.
can glucose move across the cell membrane
no
GLUT 4
on skeletal muscle and adipose tissue
insulin mediated uptake of glucose
GLUT 2
pancreatic B cells, liver/kidney.gut, leads to insulin release
metabolic consequences of insulin on liver
stimulate glycogen syn/storage. inhibit glycogen breakdown, increase protein syntehsis
inhibit glycogenolysis, inhibit ketogenesis, and inhibit gluconeogenesis.
affect of insulin on adipose
Increase triglyceride storage by promoting free FA uptake, promote esterification of free Fas, and inhibit lipolysis.
affect of insulin on skeletal muscle
Increase protein synth by increasing AA uptake. Increases glycogen synth by increasing glucose uptake, increasing glycogen synthase activity, and inhibiting glycogen phosphorylase.
main difference between glucagon and insulin
insuline promotes energy storage, glucagon promotes energy mobilization
affect of insulin on glucose in the blood
decreases
IAPP
produced by B cells. Packaged in same vesicles as insulin. Decreases glucagon secretion, inhibits GI motility, regulates appetite. Analogue can be used for type I and II diabetes.
pancreatic polypeptides
secreted by F or PP cells in pancreas. Regulated by vagus nerve and neuronal control. Regs exocrine function of pancreas, gallbladder contraction, gastric acid secretion, and GI motility.
somatostatin
secreted by delta cells, secreted in response to same stimuli as insulin. Produced also in brain, periph neurons, endocrine cells of stomach/pancreas. Inhibits insulin secretion thru activation of SSTR-5
ghrelin
Secreted by epsilon cells
GLP1
GLP1 secreted in response to meal, is insulin secretion amplifier. GLP1 promotes production and secretion of insulin and somatostatin (is neg reg of insulin). GLP1 protects and promotes growth of B cells.
what can break down GLP1
DPP-4
