Biochemistry 26: Basic Concepts In Regulation Of Fuel Metabolism By Insulin, Glucagon And Other Hormones

Front 1

Major function of insulin

Back 1

anabolic hormone that promotes storage of fat, glucose, and amino acids

Front 2

Major function of glucagon

Back 2

create fuel from amino acids, glucose and fats

Front 3

During osmotic diuresis, cell sizes will (swell or shrink)?

Back 3

during diuresis, the blood volume drops and blood is hypertonic to the cells. water moves out of the cells and they shrink

Front 4

What is HBA1C?

Back 4

glycosylated hemoglobin A. can tell us glucose levels over 12-14 weeks

Front 5

Glucagon has what effect on glycogen synthesis?

Back 5

decreases; want to use the glycogen for energy now so it should degrade glycogen

Front 6

Glucagon has what effect on gluconeogenesis?

Back 6

increases gluconeogenesis from fats and AA to create more glucose for energy

Front 7

Major stimuli for glucagon

Back 7

low blood glucose, high blood AA,

Front 8

Insulin has what effect on glucagon levels?

Back 8

decreases

Front 9

Glucagon is release from what cells?

Back 9

alpha cells of pancreas

Front 10

Epinephrine has what effect on gluconeogenesis?

Back 10

increases it

Front 11

Where are fatty acids made into glucose?

Back 11

liver

Front 12

What is C-peptide?

Back 12

proinsulin is cleaved into insulin and C-peptide. this can tell us levels of insulin also

Front 13

Function of glucokinase

Back 13

convert glucose into Glucose 6-phosphate so it doesn't leave the cell and can enter glycolysis

Front 14

Hypersecretion of insulin would lead to what levels of fatty acids in the blood?

Back 14

low levels since fat in the adipose tissue is not being broken down for energy

Front 15

How does glucose enter the Beta cells of the pancreas?

Back 15

GLUT-2

Front 16

How is insulin released from the beta cells?

Back 16

glucose enters via GLUT-2 > ATP from glucose metabolism closes K+ channel > K+ builds up in the cell and depolarizes it > Calcium channel opens > calcium comes in and mediates insulin vesicle exocytosis

Front 17

A defect in the HLA region of beta cells can lead to which type of diabetes?

Back 17

type 1; HLA defect in beta cells can lead to auto-immune attack of pancreas Beta cells

Front 18

Pancreatic islets are innervated by what nerve?

Back 18

vagus

Front 19

Epinephrine has what effect on insulin and blood glucose levels?

Back 19

epinephrine decreases insulin and increases blood glucose

Front 20

High Glucose levels in the blood have what effect on glucagon secretion?

Back 20

increase

Front 21

GIP and GLP-1 have what effect on insulin secretion?

Back 21

increase. gastric hormones that signal a heavy meal will want to get insulin ready to deal with the high nutrient levels in the blood and store them

Front 22

Fasting will lead to high levels of (insulin or glucagon)?

Back 22

glucagon

Front 23

A patient has a disorder that keeps potassium channels open, regardless of [ATP]. What type of diabetes are they at risk for?

Back 23

type 2 diabetes, can release insulin in response to glucose levels since calcium channels never open to allow for insulin release

Front 24

How do sulfonylureas work to treat diabetes?

Back 24

they close K+ channels in beta cells to allow depolarization of calcium channels and insulin release

Front 25

A high protein meal will lead to an increase in (insulin or glucagon)?

Back 25

both will increase to allow high protein levels to enter the cells

Front 26

What happens to blood triglyceride levels with high glucagon levels?

Back 26

decrease

Front 27

Why do high amino acid levels lead to increased glucagon?

Back 27

glucagon wants to take these in and use them for substrates for gluconeogenesis

Front 28

What is cleared more rapidly from blood? C-peptide or insulin?

Back 28

insulin is taken out faster, so it is good to measure C-peptide levels

Front 29

After a protein rich meal, amino acids in the blood will be taken into the cells by glucagon and insulin actions. These amino acids can be used for gluconeogenesis or protein synthesis. What determines which pathway the amino acids take?

Back 29

insulin:glucagon ratio; if there is more insulin, the amino acids will go to protein synthesis more. if there is more glucagon, the amino acids will go to gluconeogenesis more

Front 30

In diabetes mellitus type 1, what would we expect to see when measuring a patient's glucagon levels?

Back 30

increased glucagon levels, since insulin is not inhibiting it.

Front 31

Insulin uses what type of receptor?

Back 31

tyrosine kinase on plasma membrane

Front 32

After auto-phosphorylation of insulin's tyrosine kinase receptor, what happens in the receptor transduction pathway?

Back 32

IRS-1 binds to SH2 domain of receptor to lead to cell activation

Front 33

A genetic defect in G-proteins would most likely lead to what kind of blood-glucose levels?

Back 33

glucagon (and epinephrine) uses G-proteins. inability to use glucagon = low blood-glucose levels

Front 34

cAMP production is stimulated by dissociation of what G-protein subunit?

Back 34

Gs alpha

Front 35

IP3 and DAG production is stimulated by dissociation of what G-protein subunit?

Back 35

Gq alpha

Front 36

cAMP production is inhibited by dissociation of what G-protein subunit?

Back 36

Gi alpha

Front 37

Why doesn't glucagon activate glycogen breakdown in skeletal muscle?

Back 37

no glucagon receptors on skeletal muscle

Front 38

cAMP activates what kinase?

Back 38

protein kinase A

Front 39

Methylxanthines have a phosphodiesterase inhibiting function. Caffeine (a methylxanthine) should mimic what hormone? (insulin or glucagon)

Back 39

high caffeine = high cAMP = high glucagon like symptoms (glucagon uses cAMP mechanism in G-proteins)

Front 40

Vascular and smooth muscle contraction is stimulated by activation of which adrenergic receptor?

Back 40

B1

Front 41

Glycogenolysis is activated by stimulation of which adrenergic receptor?

Back 41

B2