Pbd Section 1 For Final Exam

Front 1

Which organ gets 2/3 of the absorbed glucose?

Back 1

Liver

Front 2

What is the source of 75% of glucose? 25%?

Back 2

1. Glycogenolysis (old)
2. Gluconeogenesis (new)

Front 3

What are the two intermediates when going from glycogen -> glucose?

Back 3

G1P and G6P

Front 4

What tissues have glycogen? Which can undergo glycogenolysis?

Back 4

Muscle/Liver/Kidneys have it.

Liver/Kidneys can undergo glycogenolysis.

Front 5

What is the major source of gluconeogensis from? (what compound)

Back 5

Lactate (from muscle)

Front 6

What is the name of hormones that raise blood glucose?

Back 6

Counter-regulatory hormones

Front 7

T/F The pancreas is 75% exocrine gland and 25% endocrine.

Back 7

F - 99% exocrine

Front 8

What are the two main types of tissue in the pancreas?

Back 8

Acinar
Islets of Langerhans

Front 9

What are the three main cells that make up islets of Langerhans and what do they secrete? Which type is most abundant?

Back 9

alpha cells - glucagon
beta cells - insulin (40-60% of all cells)
delta cells - somatostatin

Front 10

What enzyme is released in response to Vagal stimulation when referring to glucose metabolism?

Back 10

Glycogen Synthetase

Front 11

Sympathetic innervation of the pancreas occurs at what pancreatic cell types?

Back 11

Only alpha and beta

Front 12

Insulin is found on what chromosome?

Back 12

11

Front 13

What part of insulin is cleaved to make the active enzyme?

Back 13

C-Peptide

Front 14

T/F - The average amount of insulin being stored in the pancreas can be changed once in adulthood.

Back 14

T - Can change with aging, fasting, obesity, pregnancy.

Front 15

How much insulin is secreted daily?

Back 15

1-2mg

Front 16

Which transporter is activated for release of insulin?

Back 16

GLUT 2

Front 17

When glucose enters dermal cell what must immediately happen to it and what is the enzyme responsible?

Back 17

Phosphorylated

Glucokinase

Front 18

When glucose enters a muscle cell what must immediately happen to it and what is the enzyme responsible?

Back 18

Phosphorylated Hexokinase

Front 19

What is the action of sulfonylureas?

Back 19

Close ATPase sensitive K+ channels which then allow the entry of Ca++ by depolarizing the cell and opening voltage gated calcium channels.

Front 20

Insulin is released in a ________ manner.

Back 20

Biphasic

Front 21

When binding to a cell what dose insulin do to the levels of cAMP?

Back 21

Decreases them

Front 22

Stimulation of what catecholamine can inhibit insulin release? What second messenger does it lower to achieve this?

Back 22

Epinephrine

cAMP

Front 23

What happens to 40-50% of circulating insulin?

Back 23

Extracted by Liver

Front 24

Although C-Peptide is inactive, what can it be used for?

Back 24

Quantification - It is not degraded and therefore gives a better estimate of insulin levels

Front 25

T/F Insulin must first bind to 5-10% of receptors to initiate a response?

Back 25

True

Front 26

What second messengers are upregulated when insulin binds to its receptor? Downregulated?

Back 26

Upregulated - Tyrosine Kinase and Mg Activated Na/K ATPase

Downregulated - cAMP

Front 27

Insulin promotes ______ of glucose in cell. (the answer is not storage although this would be correct)

Back 27

Oxidation

Front 28

GLUT 1
Where is it found?
Affinity for receptor?

Back 28

RBC/Ubiquitous

Average - Operates at near maximal transport velocity

Front 29

GLUT 2
Where is it found?
Affinity for receptor?

Back 29

Liver/SI/Pancreatic beta cell

Low Affinity - However, the most linear part of its transport velocity curve is over normal physiological ranges

Front 30

GLUT 3
Where is it found?
Affinity for receptor?

Back 30

CNS

High Affinity - Because CNS needs glucose the most

Front 31

Expression of what glucose transporter is though to be depressed in Type II diabetics?

Type I diabetics?

Back 31

GLUT 2 and GLUT 4

GLUT 2 (in Type I)

Front 32

What glucose transporter is thought to be the glucose sensor at the pancreas?

Back 32

GLUT 2

Front 33

GLUT 4

Where is it found?
Expression in diabetics/obesity?

Back 33

Skeletal Muscle / Adipose / Cardiac Muscle

Decreased levels in obese and diabetic patients.

Front 34

Which glucose transporter is insulin sensitive and is continuously recycled from cytoplasm to cell membrane?

Back 34

GLUT 4

Front 35

What is the path from glucose to glycogen? What enzyme catalyzes the first step in all cells except muscle cells?

Back 35

Glucose -> G6P -> G1P -> Glycogen

Glucokinase

Front 36

What effect does insulin have on glucose-6 phosphatase, gluconeogenic enzymes, and glycogen phosphorylase in liver?

Back 36

Inhibits them because they all decrease glucose storage, which is the opposite of what insulin does.

Front 37

What class of enzymes are inhibited in the liver in the presence of insulin?

Back 37

Phosphorylase enzymes because they break down glycogen.

Front 38

T/F Insulin is slightly upregulated during exercise to facilitate the uptake of glucose into muscle cells that need it for energy.

Back 38

False, insulin is inhibited with exercise.

Front 39

What effect does insulin have on Hormone Sensitive Lipase (HSL)?

Back 39

Decreases it

Front 40

What adipose enzyme is responsible for breaking down triglycerides to glycerol and FFA's and what hormone upregulates it?

Back 40

Lipoprotein Lipase

Insulin upregulates it so that the FFA's can be absorbed in the fat cell and stored.

Front 41

What is a synthetic analog of amylin?

Back 41

Symlin

Front 42

What effect does symlin have on glucagon?

Back 42

Suppresses it

Front 43

GLP-1 (glucagon like peptide) is in what class of hormones? When is it released?

Back 43

Incretins

Released from gut after a meal

Front 44

What action do incretins have on insulin/glucagon? What is their action mediated by?

Back 44

Incretin action mediated by how much glucose enters the gut. Works by enhancing insulin secretion and suppressing glucagon secretion.

Front 45

What hormone decreases gastric emptying, preserves beta pancreatic cell function, increases satiety, and decreases food intake?

Back 45

GLP-1 (an incretin)

Front 46

What inhibits metabolism of GLP-1?

Back 46

DPP-4

Front 47

What hormone comes from the brain and is responsible for upregulating beta cells in pancreas, increasing food intake, and insulin release?

Back 47

Melanin Concentrating Hormone (MCH)

Front 48

Where do resistins come from?
What demographic are they elevated in?
What effect does it have on insulin?

Back 48

Comes from macrophages
Elevated in obese
Decreases insulin action

Front 49

What organ do resistans mainly have their effect on? What is the effect?

Back 49

Liver - Reduces insulin's inhibitory effect on the liver so more glucose enters blood.

Front 50

What chromosome is glucagon found on?

Back 50

Chromosome 2

Front 51

What two things inhibit glucagon by repressing transcription of its gene?

Back 51

Insulin and Glucose

Front 52

What is the effect of elevated calcium on glucagon secretion?

Back 52

Suppreses it

Front 53

What effect does glucagon have on insulin and somatostatin secretion?

Back 53

Increases both

Front 54

What is the major second messenger of glucagon's effects?

Back 54

cAMP

Front 55

What would be the effect of an adrenalectomy on glucose metabolism?

Back 55

Could not get full gluconeogenic effect

Front 56

What effect does glucagon have on:
HSL?
cAMP?

Back 56

HSL increased
cAMP increased

Front 57

What is the molar ratio of insulin to glucagon when:
Fasting?
Exercise?
After Meal?

Back 57

0.5 (more glucagon)
0.5 (more glucagon)
10 (more insulin)

Front 58

Which of the three main pancreatic hormones (insulin, glucagon, somatostatin) undergo post translational processing?

Back 58

All of them

Front 59

What is an effective inhibitor of every known stimulus for both glucagon and insulin?

Back 59

Somatostatin

Front 60

What are the three inhibitors of somatostatin release?

Back 60

Ach
alpha Adrenergics (Norepinephrine)
Insulin

Front 61

What effect does somatostatin have on Ca++ levels in the pancreas? What overall effect does this have?

Back 61

Decreases Ca++ by impairing uptake

This leads to lower cAMP and hence insulin is inhibited

Front 62

Would the administration of somatostatin be a useful treatment for Type 1 diabetics? Why or why not?

Back 62

Yes, because they already don't produce insulin but they have an overabundance of glucagon and somatostatin inhibits release of both.

Front 63

What gives a greater insulin spike: oral glucose or IV glucose? Why?

Back 63

Oral glucose because you get vagal stimulation this way. Also, incretins are released in GI which help mediate insulin release.

Front 64

What amino acid stimulates all three islet hormones?

Back 64

Arginine

Front 65

What effect do FFA's have on insulin and glucagon?

Back 65

Stimulate insulin
Inhibit glucagon

Front 66

What effect does cortisol have on glucagon?

Back 66

Increases sensitivity for release

Front 67

What effect do catecholamines have on the three islet hormones?

Back 67

Inhibit insulin
Inhibit somatostatin
Stimulate glucagon