Fed state, Postabsorptive, Fasting & Starvation states

Question 1

what is the major hormone controlling energy metabolism during the fed state?

Answer 1

INSULIN

Question 2

what is the main energy source in the fed state?

Answer 2

glucose

Question 3

How long does the Fed state last?

Answer 3

approximately 3 hours following a meal

Question 4

How long does the Post absorptive or early fasting state last?

Answer 4

from 3 hour to 12-18 hours after a meal.

Question 5

What is excess glucose used for? when does this occur?

Answer 5

used for fatty acid synthesis, occurs if energy intake» use of energy.

Question 6

what tissues/ organs use glucose as energy during the fed state?

Answer 6

• brain & CNS

- Muscles

Question 7

what is the effect of insulin on glucose uptake (muscle and liver)?

Answer 7

insulin increases glucose uptake (muscle) by targeting increased glucose transporter

and increases glucose uptake in the liver by targeting increased glucokinase

Question 8

what is the effect of insulin on glycogen synthesis?

Answer 8

increased glycogen synthesis by increasing glycogen synthase and decreasing glycogen breakdown by inhibiting glycogen phosphorylase

Question 9

during the fed state, glycolysis is ________ by activation of what?

Answer 9

increased by activation/ stimulation of pyruvate dehydrogenase

Question 10

what is the effect of insulin in the fed state on fatty acid synthesis and Triacylglyceride synthesis ?

Answer 10

both are increased. fatty acid synthesis is increased by targeting acetyl CoA carboxylase and TAG synthesis is increased by targeting lipoprotein lipase (LPL)

Question 11

where are branched amino acids metabolsed ?

Answer 11

the muscles

Question 12

what is the major source of glucose in the EARLY fasting state?

Answer 12

Glycogenolysis , glycogen in liver + muscles are almost depleted during an overnight fasting

Question 13

Do glycogenesis and lipogenesis occur in the early fasting state?

Answer 13

NO!

Question 14

what process (Glycogenesis, glycogenolysis, glyconeogensis, glycolysis) is increased in the early fasting state?

Answer 14

Gluconeogensis and Glycogenolysis

Question 15

what are the important sources for gluconeogenesis during early fasting?

Answer 15

• Lactate and alanine

- glycerol

Question 16

What happens in the liver during the postabsorptive (early fasting state)?

Answer 16

• glycogenolysis= breakdown of glycogen to glucose
• gluconeogensis= Lactate, Alanine and glycerol to glucose
• Fatty acids undergo B-oxidation and metabolized to TG

Question 17

what happens to glucose in the CNS + the brain during postabsorptive state?

Answer 17

Glucose is catabolized for energy with no return of gluconeogenic precursors

Question 18

what happens to glucose in the RBCs during Postabsorptive state?

Answer 18

glucose is broken down to Lactate and ATP through the pentose phosphate pathway.

Question 19

What hormones are involved in early fasting state regulation?

Answer 19

• glucagon
• epinephrine
• catecholamines
• glucocorticoids

Question 20

what 2 hormones initiate hepatic (liver) glycogenolysis during the early fasting state?

Answer 20

Glucagon and epinephrine

Question 21

what initiates glycogenolysis in muscles during early fasting?

Answer 21

catcholamines

Question 22

what inhibits glucose uptake by muscles in the postabsorptive state?

Answer 22

Catecholamines

Question 23

how long does it take for glycogen to be depleted following a meal?

Answer 23

18 hours

Question 24

which hormones stimulate gluconeogensis in the early fasting state?

Answer 24

glucagon and epinephrine

Question 25

what stimulates proteolysis (breakdown of amino acids for gluconeogensis?

Answer 25

Glucocorticoids

Question 26

glucagon secretion is stimulated by_____?

Answer 26

Alanine

Question 27

what do low levels of insulin affect?

Answer 27

causes decreased glucose utilization and increased lipolysis.

Question 28

what occurs in the liver during the Fasting state (18-48 hour)?

Answer 28

gluconeogensis

glycogenolysis

Question 29

ketogenic amino acids are broken down to ketones and used as what?

Answer 29

energy source for Brain + CNS

Question 30

acetyl co A synthesizes what in the liver?

Answer 30

ketone bodies

Question 31

when the body is in starvation state the levels of ketone bodies in the blood are _____ and glucose levels are _____

Answer 31

HIGH. LOW

Question 32

when does the fasting state start and how long does it last?

Answer 32

from 18 hours up to 2 days following a meal

Question 33

How long can starvation or long-term fasting last?

Answer 33

for a few weeks

Question 34

What metabolic pathway is favored in the starvation state?

Answer 34

lipolysis (fat as energy source)

Question 35

what is the last thing the body wants to break down for energy?

Answer 35

protein! we must spare it!

Question 36

What is the energy source for most tissues (except the brain) during starvation?

Answer 36

Fatty acids

Question 37

what is the main glucose precursor in starvation state?

Answer 37

glycerol

Question 38

What happens to oxaloacetate and the TCA cycle during the fasting state?

Answer 38

oxaloacetate is not produced because TCA intermedates are used for gluconeogensis

Question 39

what does acertyl Co A form during the starvation state?

Answer 39

Acetoacetyl CoA & ketone bodies

Question 40

what is the main energy source for the brain during starvation?

Answer 40

ketone bodies

Question 41

during starvation state, glucose use ______ and ketogenesis ________

Answer 41

decreases, increases

Question 42

what do muscle use for energy in preference to glucose and amino acids during the starvation state?

Answer 42

fatty acids

Question 43

what happens in the kidney during the starvation state?

Answer 43

gluconeogenesis from glutamine