Endocrine energy regulation Flashcards
(39 cards)
What other hormones apart from insulin and glucagon can influence glucose homeostasis
Epinephrine
Cortisol
Growth hormone
Thyroid hormone
Secretin
Cholecystokinin
What is the only hormone that lowers bood glucose
Insulin
What receptors are stimulated by insulin and which by glucagon/epinephrine
Insulin- RTK
Glucagon, epinephrine ->GPCR
how endocrine portion of pancreas in called
Islets of langernas
what is secreted by acinar and duct cells? to what portion of paracrine they are referred?
What cells are founf in islets of langerhans and what they secrete
where glucagon, somatostatin and pancreatic polypeptide are produced apart from pancreas?
Gastrointestinal mucosa
What is morphology of islets of Langerhans
islets highly vascularized (5 to 10 x blood flow of exocrine pancreas)
v blood first supplies centrally located B cells i.e. detects glucose levels
v then blood travels to more peripheral A and D cells i.e. exposed to insulin secreted by B cells
how islet cell hormones interact between each other?
How glucagon and insulin are produced?
what are nutrients, gastrointestinal hormones, hormones and autonomic nerves which control the release of insulin form beta cells
major factors controlling insulin secretion
epinephrine through alpha receptors
what nutrients, GI hormones, hormones and nerves control release of glucagon
What is the longest nerve in our body
Vagus nerve, number 10
what is the functional of vagus nerve
v Acts as a sensory neuron and
as a motor neuron (providing
and receiving signals from
peripheral organs)
v Main neuronal coordinator of
appetite control, digestion
and metabolism
v Release of acetylcholine
(cholinergic) in the pancreas
stimulates insulin release
how insulin get released from beta cells
- v Uptake of glucose by the type 2 facilitative glucose transporter (Glut 2)
- Aerobic glycolysis and increase of the ATP/ADP ratio.
- Inhibition of ATP-sensitive K+ channels → reduction of K+ efflux → membrane depolarization
- Opening of voltage gated Ca2+ channels (VDCC)
- Increased intracellular Ca2+ triggers exocytosis of insulin containing granules
- Opening of Ca2+ activated potassium channels (K-Ca), leading to the repolarization of the membrane (resetting)
- Metabolic coupling factors generated during glucose metabolism facilitate exocytosis and/or proinsulin synthesis (amplification pathway). Examples are plasma FFA (stimulates exocytosis via G-protein receptor) and intracellularly formed succinate.
- Glucagon-like peptide 1 (GLP-1 from intestine) or related peptides bind to GLP-1 receptors and trigger cAMP production. It potentiates the amplification pathway, ion channels and exocytosis
what is happeing with glucose metabolism overall after meal and when fasting
what is normal glucose level during fasting , after meal and when glycosuria
v Serum glucose in the fasting stage 3-5 mM
v Rise to 7 mM after meal (glycosuria if exceeding 10 mM)
anabolic effects of insulin
synthesis of protein, lipid and glycogen and
inhibition of their degradation (usage of glucose)
v Insulin promotes cell growth. It is essential for normal growth and
development
Key target tissues of insulin
Insulin promotes glucose uptake in muscle and adipose tissue
by increasing the Glut 4 transporters on the cell surface
and cardiac muscle
is insulin stopped to be secreted ever?
Insulin is continuously secreted to enable peripheral tissues to uptake glucose
Glucose supresses ___ (hormone) secretion
GH, which reduces glucose uptake and increases lypolysis
where glut2,glut 3, glut 4 is found and their specifics
how facilitated uptake via glut 2 is maintained
The concentration gradient of (non-phosphorylated) glucose
insulin receptor-> ___ pathway->glut 4 is brought to the surface
PI3K pathway
