Flashcards in Fed Fast Deck (34)
what are the main hormone regulators of BGL?
where is GLUT 2 used?
used for liver uptake of glucose
used for liver release of glucose
It is the principal transporter for transfer of glucose between liver and blood, and for renal glucose reabsorption.
which organ buffers BGL?
which tissue stores and degrades glucose?
when is GLUT 4 used?
in adipose tissue after a meal to take up glucose and FA --> then TAGS are synthesized
muscles use to take up glucose
Heart uses it too
what do muscles do after a meal?
take up glucose via GLUT 4 and amino acids and perform glycogen synthesis and protein synthesis
what is GLUT 1 for?
the brain - it always needs glucose!
what is postprandial?
2-3 hours after a meal - high insulin/glucagon ratio
what has a central role in reducing postprandial glucose levels?
what happens in the postprandial phase?
dietary monosaccharide take up by intestinal mucosal cells via SGLT -1 and GLUT 5 and are released via GLUT 2 into the portal vein?
what is the order to events after eating!
glycogen stores filled
glycolysis - liver, adipose, muscle
FA, TAG and cholesterol synthesis
what is postabsorptive phase?
5-7 hours after food intake - low insulin/glucagon ratio
what is the order of events in postabsorptive phase?
release glucose - glycogen degrad, gluconeogenesis
hepatocytes release free glucose by GLUT 2
mobilize TAGS - FA + glycerol
beta oxidation - liver and muscle
ketone body synthesis - liver
what is the major role of the liver in postabsorptive phase?
to prevent a major drop of BGL
when are liver glycogen stores empty
after one day
what happens during early phases of starving/fasting? - 2,3 days after food
release of glucose in blood by liver glycogen degradation and gluconeogenesis
what happens after liver glycogen stores are depleted (after 24 hours)?
only gluconeogenesis will provide blood glucose
what happens under stress situations? - just read...
-the pituitary gland releases ACTH which stimulates release of cortisol from the adrenal cortex
-Cortisol leads in the adrenal medulla to methylationof norepinephrineto epinephrine (PNMT, using SAM) and release of both catecholaminesinto the blood
-Epinephrine inhibits insulin release from b-cells of pancreas and stimulates glucagon release from a-cells of pancreas
what is metabolic homeostasis?
results from communication between tissues regarding fuel energy in the body
how is metabolic homeostasis achieved?
by availability of substrates via levels of hormones and also some from the nervous system
why is a continuously high BGL bad?
leads to non-enzymatic glycosylation of proteins, including hemoglobin HbA1 which leads to HbA1c.
where are there glucagon receptors? where are there insulin receptors?
glucagon receptors - liver heptaocyte
insulin receptors - found in many cells
how does epinephrine support liver metabolism?
supports liver glycogen degadation (phosphorylation cascade)
how does cortisol support liver metabolism?
supports gluconeogenesis by induction of PEPCK
what is needed for long term gluconeogenesis?
what inhibits insulin release?
what stimulates insulin release?
glucose and aa - esp. leucine (dietary ess. aa) and arginine
what inhibits glucagon release?
what is glucagon release stimulated by?
epinephrine and aa - esp. alanin and arginine
what leads to both release of insulin and glucagon?
what are the key factors in regulation of inside cells and via hormones in blood?
- availability of substrate - min
-allosteric regulation by positive / negative heterotropic effectors - min
-covalent modification of enzymes (phos/dephos) - min --> hr
-synthesis of new enzymes molecules - hr--> days
what does active protein kinase A (cAMP) do?
phos key enzymes - associated with glucagona nd epinephrine
what does high insulin do to lipoprotein lipase?
activate it! - to synthesize TAGS and store FA!