Endocrine Pancreas

Front 1

What endocrine products does the pancreas synthesize and release?

Back 1

Hormones: glucagon, insulin, somatostatin

Front 2

What exocrine products does the pancreas synthesize and release?

Back 2

Enzymes

Front 3

Where does the pancreas release hormones such as insulin, glucagon, and somatostatin?

Back 3

Into the portal vein (circulation)

Front 4

Where does the pancreas release enzymes?

Back 4

Into the intestine

Front 5

What is the major stimulus for endocrine secretion?

Back 5

Glucose

Front 6

What is the major stimulus for exocrine secretion?

Back 6

Secretion depends on phases of digestion

Front 7

Secretion of islet hormones a)_________ and b)_________ is coordinated with the secretion of c)___________________

Back 7

a) insulin

b) glucagon

c) exocrine pancreatic enzymes

Front 8

What regulates insulin and glucagon secretion?

Back 8

The entry of nutrients into GI tract
and
GI hormones

Front 9

What cells of the pancreas secrete insulin?

What is the percentage of these cells?

Back 9

B (beta) cells of the Islets of Langerhans

65-70%

Front 10

What cells of the pancreas secrete glucagon?

What is the percentage of these cells?

Back 10

A (alpha) cells of the Islets of Langerhans

about 20%

Front 11

What cells of the pancreas secrete somatostatin?

Back 11

D (delta) cells of the Islets of Langerhans

Front 12

What inhibitory peptide of the pancreas inhibits islets cell secretion?

Back 12

Somatostatin

Front 13

Is insulin an anabolic hormone or a catabolic hormone?

Back 13

Anabolic

Front 14

Is glucagon an anabolic hormone or a catabolic hormone?

Back 14

Catabolic

Front 15

Levels of which pancreatic hormone rise when body has excess of nutrients?

Back 15

Insulin

Front 16

Which pancreatic hormone allows the body to use carbohydrates as an energy source and store nutrients?

Back 16

Insulin

Front 17

Levels of which hormone rise when the body is in a state of nutrient/food deprivation?

Back 17

Glucagon

Front 18

When glucagon levels are high, what nutrient reserves are mobilized as an energy source?

Back 18

Glycogen, fat, and protein

Front 19

Increased plasma glucose stimulates __________ secretion

Back 19

Insulin

Front 20

Decreased plasma glucose stimulates ___________ secretion

Back 20

Glucagon

Front 21

Insulin __________ glucagon secretion

Back 21

inhibits

Front 22

Glucagon _________ insulin secretion

Back 22

stimulates

Front 23

Insulin increases activity of which metabolic processes?

Back 23

Glucose oxidation
Glycogen synthesis
Fat synthesis
Protein synthesis

Front 24

Glucagon increases activity of which metabolic processes?

Back 24

Glycogenolysis (glycogen degradation)
Gluconeogenesis (glucose from pyruvate, which comes from acetyl coa)
Ketogenesis

Front 25

The fasting plasma glucose level is about _____ mg/dl with a range of ________ mg/dl

Back 25

90 mg/dl

70-110 mg/dl

Front 26

After a meal, plasma glucose _________ and stimulates __________ secretion

Back 26

increases

insulin

Front 27

During overnight fasting, plasma glucose ___________, insulin secretion ___________, and glucagon secretion __________.

Back 27

Plasma glucose decreases

Insulin secretion decreases

Glucagon secretion remains steady

Front 28

What are the serum stimulators of insulin secretion?

Back 28

elevated glucose (>100 mg/dl)
elevated amino acids
elevated free fatty acids
elevated ketone bodies

Front 29

What are the serum inhibitors of insulin secretion?

Back 29

low glucose
low amino acids
low free fatty acids

Front 30

What hormones stimulate insulin secretion?

Back 30

Gastroinhibitory peptide (GIP), Glucagon-like peptide-1(GLP-1)
gastrin
cholescystokinin (CCK)
secretin
vasoactive peptide (VIP)
Glucagon
epinephrine (β2-AR)

Front 31

What hormones inhibit insulin secretion?

Back 31

Somatostatin
Epi/Norepi (alpha2-AR)

Front 32

Insulin secretion is caused by the ____________ nervous system.

Back 32

parasympathetic (Ach)

Front 33

Insulin inhibition is caused by the _______________ division of the autonomic nervous system.

Back 33

sympathetic (alpha2-AR)

Front 34

Steps of insulin secretion:
a) Glucose enters the _________ via ___________ transporter

b) Glucose → _________ → → _______ production

c) ATP binds to the _________________ → ↓K+ efflux → β cells ___________
d) "2nd answer to c" causes the _____________ channels to open → _______ influx → _____ stimulates insulin release by __________

Back 34

a) β cells, GLUT2

b) glucose-P, ↑ATP

c) ATP-sensitive K+ channels (KATP), depolarization

d) voltage-gated Ca2+, ↑ Ca2+, Ca2+, exocytosis

d)

Front 35

Insulin secretion in beta-cells:

a) is _________ by ACETYLCHOLINE, GLUCAGON, beta-2-adrenergic stimulation

b) is ___________ by alpha2-adrenergic stimulation (the predominant response to sympathetic stimulation is mediated via alpha2-AR), SOMATOSTATIN

Back 35

a) increased

b) decreased

Front 36

What is a polypeptide containing two chains of amino acids (A and B chain)?

Back 36

Insulin

Front 37

What makes insulin antigenic?

Back 37

Minor species differences in the amino acid composition

Front 38

Insulin synthesis!

Initially, a)___________ is the inactive form that is secreted into the b) ____________.
Post-translational processing clips the _____________ and forms the disulfide bridges (proinsulin).
The polypeptide is clipped at d)____(#) positions to release the intervening chain C (C peptide is detached before secretion).
e) __________ and f) __________ are secreted by g) ____________

Back 38

a) preproinsulin
b) endoplasmic reticulum
c) N-terminal signal sequence
d) 2
e) active insulin
f) C peptide
g) exocytosis

Front 39

T/F

Most of insulin and C-peptide are released in unequal molar amounts.

Back 39

False!

90 -97% of insulin and C-peptide are released in equimolar amounts

Front 40

What can be measured in plasma and its level provides an index of the β cell function?

Back 40

C-peptide

Front 41

What reduces glomerular hyperfiltration and reduces urinary albumin excretion in patients with diabetes?

Back 41

C-peptide

Front 42

What reduces glomerular hyperfiltration functions in repair of the muscular layer of arteries?

Back 42

C-peptide

Front 43

T/F

C-peptide functions are not fully understood.

Back 43

True!

Front 44

Insulin receptors are ________________ receptors.

Back 44

tyrosine-kinase (Tk) linked

Front 45

Insulin receptors are activated by what?

Back 45

Binding of insulin to the receptor

Front 46

When insulin binds its own receptor, the activated insulin receptor phosphorylates insulin-receptor substrate and induces effects on cellular:

Back 46

metabolism
membrane transport
activity of transcription factors

Front 47

What hormone promotes cellular growth and survival (brain cells)?

Back 47

Insulin

Front 48

What hormone inhibits β–oxidation of fatty acids?

Back 48

Insulin

Front 49

What hormone promotes transmembrane transport of potassium, magnesium, and phosphate ions into cells?

Back 49

Insulin

Front 50

Insulin-dependent glucose transport is via:

This is located where?

Back 50

GLUT4

adipose or skeletal/cardiac muscle cell

Activation of insulin receptors → activation of phosphoinositide-3-kinase → translocation of the GLUT4-containing endosomes into the cell membrane.

GLUT4 has a high affinity for glucose.

Front 51

Insulin-independent glucose transport is via:

This is located where?

Back 51

GLUT2

liver cell

Front 52

Name the transporter:

Sodium-dependent transport. Cotransports molecule of glucose or galactose. Does not transport fructose.

Major expression sites: Intestinal mucosa and kidney tubules

Back 52

SGLUT1 and SGLUT2

Front 53

Name the transporter:

Transports glucose (high affinity) and galactose, not fructose. Expressed in many cells.

Major expression sites: Brain, erythrocyte, endothelial cells, fetal tissues, cardiac myocytes

Back 53

GLUT-1

Front 54

Name the transporter:

Transports glucose, galactose and fructose. A low affinity, high capacity glucose transporter; serves as a "glucose sensor" in pancreatic beta cells.

Major expression sites: Liver, pancreatic beta cell, small intestine, kidney

Back 54

GLUT-2

Front 55

Name the transporter:

Transports glucose (high affinity) and galactose, not fructose. The primary glucose transporter for neurons.

Major expression sites: Brain, placenta and testes

Back 55

GLUT-3

Front 56

Name the transporter:

Transports fructose, but not glucose or galactose. Present also in brain, kidney, adipocytes and muscle.

Major expression sites: Small intestine and sperm

Back 56

GLUT-5

Front 57

What hormone is a single-chain peptide?

Back 57

Glucagon

Front 58

What is the second messenger for glucagon?

Back 58

cAMP

Front 59

What are possible stimuli for glucagon secretion?

Back 59

Decreased serum glucose
Increased serum amino acids (arginine, alanine)
Sympathetic stimulation (via β2-AR)
Stress
Prolonged fasting
Exercise

Front 60

What are possible inhibitors of glucagon secretion?

Back 60

Somatostatin
Insulin
↑ Serum glucose

Front 61

Glucagon stimulates glycogenolysis and gluconeogenesis in what organ?

Back 61

The liver

Front 62

What hormone increases plasma levels of free fatty acids and ketoacids while decreasing level of amino acids?

Back 62

Glucagon

Front 63

T/F

Glucagon and Insulin have anatagonistic effects at numerous steps in hepatic glucose and fatty acid metabolism.

Back 63

True!

Front 64

How does glucagon decrease plasma levels of amino acids?

Back 64

By increasing uptake of amino acids by the liver

Front 65

A supply of glucose is absolutely required to sustain function of which organ?

Back 65

The brain

Front 66

Does glucagon increase or decrease cortisol release?

Back 66

Increase

Front 67

Does glucagon increase or decrease epinephrine release?

Back 67

Increase

Front 68

What hormone stimulates expression of the Insulin gene?

Back 68

Growth Hormone

Front 69

What hormone induces resistance to the action of insulin?

Back 69

Growth Hormone

Glucose uptake by muscle and adipose cells is inhibited, and the plasma glucose concentration rises. Hyperinsulinemia results in compensation.

Front 70

What hormone is considered a diabetogenic hormone?

Back 70

Growth Hormone

Front 71

Growth hormone __________ gluconeogenesis and __________ glucose absorption in the intestine.

Back 71

increases, increases

Front 72

Growth hormone __________ plasma glucose levels.

Back 72

increases

Front 73

Growth hormone, glucocorticoids and catecholamines all __________ the plasma glucose level.

Back 73

Increase

Front 74

What decreases glucose uptake by muscle tissue (by reducing sensitivity to insulin)?

Back 74

Glucocorticoids

They also stimulate gluconeogenesis and stimulate glycogen synthesis when plenty of glucose is available

Front 75

What stimulates glycogenolysis in the liver and in the muscle, therefore increasing muscle glucose supply and glycolysis?

Back 75

Catecholamines

Also, released lactate serves as a substrate for hepatic gluconeogenesis

Front 76

What stimulates gluconeogenesis directly through α1 receptors in the liver?

Back 76

Catecholamines

Front 77

T/F

Catecholamines stimulate insulin secretion and stimulate insulin-stimulated glucose uptake by muscle tissue.

Back 77

False!

Catecholamines actually inhibit insulin secretion and inhibit insulin-stimulated glucose uptake by muscle tissue.

Front 78

Does exercise increase or decrease skeletal glucose?

Back 78

Increases

Front 79

What are the normal, impaired, and diabetic glucose concentration ranges during fasting?

Back 79

Normal - < 110mg/dl
Impaired glucose control – 100-126 mg/dl
Diabetes – > 126 mg/dl

Front 80

What are the normal and diabetic glucose concentration ranges after a meal?

Back 80

Normal: 200 mg/dl
Diabetes: >200mg/dl after 2 hours after a meal

Front 81

For a glucose tolerance test:

a) When do you perform it?

b) How much glucose do you take orally for the test?

c) When do you measure the plasma glucose level?

d) What are the normal and diabetic ranges at this time?

Back 81

a) after an overnight fast

b) 75g of glucose

c) 2 hours after taking it

d) N:< 200mg/dl; diabetes: >200 mg/dl

Front 82

Hyperglycemia leads to elevated intracellular glucose in specific cell types and may contribute to pathological changes. What cell types are these?

Back 82

Endothelial cells in the retina, kidney, and capillaries associated with peripheral nerves

Front 83

What are some complications related to diabetes, due to glycosylation of target proteins and oxidative stress?

Back 83

Microvascular dysfunctions:
Retinopathies (microaneurisms, retinal hemorrhage)
Neuropathies
Nephropathies (renal failure)

Macrovascular dysfunctions:
atherosclerosis (endothelial damage + dyslipidemia)