Metabolic Regulation In Injury

Question 1

Does insulin phosphorylate or dephosphorylate things?

Answer 1

Dephosphorylate

Question 2

Cascade that glucagon stimulates

Answer 2

.cAMP/PKA
. Causes release of glucose from liver via glycogen catabolism, gluconeogenesis, and FA release from adipose
. Epinephrine does same thing

Question 3

What state is caused by injury

Answer 3

. Hypermetbolic styate

. basal metabolic rate (BMR) inc. proportional to injury

Question 4

Cytokines

Answer 4

. Peptide signaling molecule assoc. w/ immune response
. Important ones: tumor necrosis tractor (TNF), IL-1, IL-6, interferon-gamma (IFN)
. Initiate and regulate metabolic response to injury.infection

Question 5

Cortisol

Answer 5

. Steroid hormone synthesized in adrenal gland
. Slow time scale
. Generated normally in cycle w/ circadian clock
. Counter-regulatory hormone (opposes insulin, promotes catabolic processes)

Question 6

Effects of cortisol

Answer 6

. Skeletal muscle: protein catabolism activated, synthesis inhibited
. Liver: gluconeogenesis stimulated
. Inhibited infmallatory response
. Inhibits fibroblast formation slowing wound healing

Question 7

What happens I there is too much cortisol?

Answer 7

. From adrenal gland tumor (Cushing’s)

. Symptoms: truncates obesity, insulin resistance causing DM, poor immune system, poor wound healing

Question 8

What happens w/ too little cortisol

Answer 8

. Most common Addison’s disease
. Symptoms: hypoglycemic from poor gluconeogenesis
. Dec. bp
. Stress causes drop in bp and patient goes into shock

Question 9

In injury, balance btw insulin and counter-regulatory hormones shift in direction of ____

Answer 9

Counter regulatory hormones

. Causes insulin resistance

Question 10

Basal metabolic rate

Answer 10

. Energy required by individual during physical, digestive, and emotional rest

Question 11

What determines BMR

Answer 11

. Body surface area: greater surface area, more heat loss
. Age: kids need more energy than adults to grow
. Women have lower than men
. Regular exercise inc. BMR

Question 12

How does starvation effect BMR

Answer 12

. Dec. up to 50%

Question 13

What percentage increase in BMR for each degree C rise in body temp?

Answer 13

12% inc.

Question 14

Effect of burns, severe infections, and prolonged lack of food on BMR

Answer 14

. Burns: inc. BMR 2 fold
. Severe infections: inc. BMR 50%
. Prolonged lack of food: dec. BMR

Question 15

How does hypermetabolism help in injury

Answer 15

. Hyperglycemia for cells using aerobic metabolism in injured area (fibroblasts, macrophages, leukocytes)
. Kidney uses more glucose than usual
. AA released from skeletal muscle is muscle is uninjured to use for gluconeogenesis, Gln in intestines, substrates for protein synthesis by liver, plasma cells that make antibodies, and cells in wound healing

Question 16

How does preoduction of proteins by liver change in response to injury?

Answer 16

. Makes less of albumin and transferrin
. Makes more C-reactive protein, serum amyloid A, haptoglobin (combines w/ harmful substances released during cell lysis), fibrinogen (promotes/regulates hemostasis), ceruloplasmin (delivers Cu to wound for collagen biosynthesis), component C3 (complement)

Question 17

Complement cascade

Answer 17

. Initial step: antibody binds to infectious agent
. Final step causes lysis of foreign cell
. Series of step involving zymogens (key steps are proteolytic cleavage and conformational changes)
. Found in blood and lymph

Question 18

C-reactive protein

Answer 18

. Protein Marker of inflammation
. Stimulates complement and promotes interaction btw pathogens and phagocytic cells
. Binds chromatin and histones to prevent autoimmune problems
. Enhances chemotaxis and phagocytosis
. Modulates platelet activation
. Inhibits IL-1 and TNF to regulate inflammation

Question 19

Chromatin

Answer 19

Human DNA complexed w/ protein

Question 20

Histones

Answer 20

Proteins found to DNA

Question 21

Changes in lipid metabolism in response to injury

Answer 21

. Inc. counter-regulatory hormones cause stimulation in HSL via PKA phosphorylating it after activation by adenylate cylase and cAMP
. Helps catabolize TAGs w/ other lipases
. FAs exported and taken up by other tissues

Question 22

Ketogenesis w/ injury

Answer 22

. Doesn’t happen

. There is insulin available

Question 23

Muscle in injury

Answer 23

. Protein catabolism leads to muscle weakness
. Nitrogen excretion decreases if you provide good nutritional support (5% dextrose infusion)
. Percent muscle loss by administering propranolol

Question 24

Propranolol

Answer 24

. Inhibits Epinephrine
. Counteracts hypermetbaolic state assoc. w/ injury
. Prevents excess catabolism and muscle loss
. Improves aerobic response to exercise in massively burned children