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Biochemistry Post Midterm > Fed Fast > Flashcards

Flashcards in Fed Fast Deck (34):
1

what are the main hormone regulators of BGL?

-insulin
-glucagon
-epinephrine
-cortisol

2

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.

3

which organ buffers BGL?

liver

4

which tissue stores and degrades glucose?

adipose tissue

5

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

6

what do muscles do after a meal?

take up glucose via GLUT 4 and amino acids and perform glycogen synthesis and protein synthesis

7

what is GLUT 1 for?

the brain - it always needs glucose!

8

what is postprandial?

2-3 hours after a meal - high insulin/glucagon ratio

9

what has a central role in reducing postprandial glucose levels?

the liver

10

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?

11

what is the order to events after eating!

glycogen stores filled
glycolysis - liver, adipose, muscle
FA, TAG and cholesterol synthesis
protein synthesis

12

what is postabsorptive phase?

5-7 hours after food intake - low insulin/glucagon ratio

13

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

14

what is the major role of the liver in postabsorptive phase?

to prevent a major drop of BGL

15

when are liver glycogen stores empty

after one day

16

what happens during early phases of starving/fasting? - 2,3 days after food

release of glucose in blood by liver glycogen degradation and gluconeogenesis

17

what happens after liver glycogen stores are depleted (after 24 hours)?

only gluconeogenesis will provide blood glucose

18

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

19

what is metabolic homeostasis?

results from communication between tissues regarding fuel energy in the body

20

how is metabolic homeostasis achieved?

by availability of substrates via levels of hormones and also some from the nervous system

21

why is a continuously high BGL bad?

leads to non-enzymatic glycosylation of proteins, including hemoglobin HbA1 which leads to HbA1c.

22

where are there glucagon receptors? where are there insulin receptors?

glucagon receptors - liver heptaocyte
insulin receptors - found in many cells

23

how does epinephrine support liver metabolism?

supports liver glycogen degadation (phosphorylation cascade)

24

how does cortisol support liver metabolism?

supports gluconeogenesis by induction of PEPCK

25

what is needed for long term gluconeogenesis?

cortisol

26

what inhibits insulin release?

epinephrine

27

what stimulates insulin release?

glucose and aa - esp. leucine (dietary ess. aa) and arginine

28

what inhibits glucagon release?

glucose

29

what is glucagon release stimulated by?

epinephrine and aa - esp. alanin and arginine

30

what leads to both release of insulin and glucagon?

arginine

31

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

32

what does active protein kinase A (cAMP) do?

phos key enzymes - associated with glucagona nd epinephrine

33

what does high insulin do to lipoprotein lipase?

activate it! - to synthesize TAGS and store FA!

34

what uses BCAA for energy metaoblism

muscle cells insulin ruling