Intro To Endocrine, Review Gluc And Fat Metabolism

Front 1

satiety hormone secreted by adipose tissue

Back 1

leptin

Front 2

hormone increasing renal sodium excretion secreted by heart

Back 2

atrial natriuretic peptide

Front 3

Receptors with tyrosine or serine kinase activity are generally_______ receptors

Back 3

growth factor

Front 4

thyroid hormones are derived from ________

Back 4

tyrosine

Front 5

active form of vitamin D

Back 5

1,25 dihydroxyvitamin D

Front 6

what kind of receptor does vit D bind to?

Back 6

nuclear receptor (similar to steroid hormones)

Front 7

thyroid hormones have mech of action similar to _____

Back 7

steroid hormones in that they bind to nuclear receptors and alter gene transcription

Front 8

Secretion of a stimulatory hormone from hypothalamus results in secretion of _______ hormone

Back 8

pituitary

Front 9

What happens (briefly) in Hashimoto's thyroiditis?

Back 9

hypothyroidism due to autoimmune destruction of thyroid tissue

Front 10

Graves disease causes ________

Back 10

hyperthyroidism. it's an example of an autoimmune disease stimulating hormone production

Front 11

Most tumors within endocrine glands are _______

Back 11

benign adenomas

Front 12

Adrenal adenoma causes ____

Back 12

Cushing syndrome

Front 13

Parathyroid adenoma causes

Back 13

hyperparathyroidism

Front 14

Stimulatory tests: what are they used to determine?

Back 14

If someone responds appropriately to an endocrine stimulus for icnreased hormone production

(Confirms dx of decreased/hypo function)

Front 15

Suppressive tests: what are they used to determine?

Back 15

Uses normal inhibitory feedback responses to determine whether patient responds appropriately with suppression of hormone production.

Used in the setting where there appears to be excess production.

Front 16

significance of AMP kinase

Back 16

important energy sensor.

Stimulates energy production (glucose, FA oxidation); inhibits energy storage (gluconeogenesis, FA synthesis) when AMP binds to AMPK and activates

Front 17

What activates AMP kinase?

Back 17

AMP binding

Front 18

Serum glucose levels peak ______ after initiation of a meal

Back 18

1 hour

Front 19

normal fasting glucose levels

Back 19

60-100, 80 mg/dl being average

Front 20

As plasma glucose declines below normal, what hormones are secreted?

Back 20

Glucagon
Catecholamines
Cortisol
Growth hormone

Front 21

as serum glucose rises ___ is released

Back 21

insulin

Front 22

which cells sense a rise in glucose and secretes proinsulin?

Back 22

beta cells within pancreatic islets of Langerhans

Front 23

Generally, how does hyperglycemia stimulate insulin secretion?

Back 23

1) Glucose binds to GLUT2

2) Undergoes glycolysis --> intracellular concentrations of ATP rise

3) ATP molecules bind to sulfonylurea subunit of the K+ channel and prevent efflux of K ions from flowing out of the cell.

4) Transmembrane calcium channels open, calcium rushes in

5) Rise of intracellular calcium promotes exocytosis of insulin-containing vesicles

Front 24

What do ATP bind to in order to prevent efflux of K ions from flowing out of the cell?

Back 24

sulfonylurea subunit of the K+ channel

Front 25

What is GLUT2?

Back 25

Binds and transports glucose from extracellular space to cytoplasm of beta cell

Front 26

What is GLUT4?

Back 26

Transports glucose from extracellular space to cytoplasm of muscle cell.

It is insulin sensitive - only transports when insulin resides on cellular plasma membrane

Front 27

What initiates the phosphorylation cascade ultimately leading to the translocation of vesicles containing GLUT4 from cytosol to plasma membrane, where it can transport glucose?

Back 27

insulin binding to insulin receptor

Front 28

What is the fate of intramuscular glucose?

Back 28

1) Minority is oxidized for energy
2) Most is used as storage in form of glycogen

Front 29

_____ stimulates glycogen synthetase

Back 29

insulin

Front 30

_______ inhibits liver from secreting glucose

Back 30

Insulin

Front 31

When insulin levels are low, the liver releases glucose. What organ(s) are using this, primarily?

Back 31

The brain, which can't oxidize FAs

Front 32

What is the source of the hepatic glucose released when insulin is low?

Back 32

Gluconeogenesis (hepatic synthesis of glucose); Glycogenolysis (Breakdown of stored glycogen)

Front 33

responsible for switch in preferred energy producing substrate from FAs to glucose

Back 33

postprandial state (insulin)

Front 34

Turns off FA delivery and FA oxidation

Back 34

insulin

Front 35

how are free FAs produced?

Back 35

breakdown of triacylglycerides into free FAs and glycerol

Front 36

What does hormone-sensitive lipase (HSL) do?

Back 36

catalyzes breakdown of triglyceride --> diacylglycerol (DAG)

Front 37

What does adipose triglyceride lipase (ATGL) do?

Back 37

Catalyzes breakdown of triacylglycerol and DAG to glycerol and free FAs.

Front 38

What increases the function of the lipases?

Back 38

Catecholamines, cortisol, growth hormone.

(This is because they counter insulin action)

Front 39

When we eat, what type of fat rises in serum and what type falls?

Back 39

1) Triacylglycerides packaged in chylomicrons rise

2) Nonesterified, free FAs (derived from fat cells) fall, because of insulin

Front 40

Inhibits FA transport into muscle

Back 40

Insulin

Front 41

First and rate limiting step in FA synthesis

Back 41

Generation of Malonyl CoA from acetyl coA by Acetyl CoA carboxylase

Front 42

What enzyme stimulates Generation of Malonyl CoA from acetyl coA

Back 42

Acetyl CoA carboxylase (ACC)

Front 43

What stimulates enzymatic activity of ACC?

Back 43

Insulin (again, example of insulin promoting fat storage)

Front 44

allosteric inhibitor of Carnitine Acetyltransferase

Back 44

malonyl coA

Front 45

What is the implication of malonyl CoA inhibiting Carnitine Acetyltransferase?

Back 45

The new free FAs synthesized can't be transported into mitochondria and oxidized for ATP generation

Front 46

The major glucose transporter for liver is ____, not ____ as in muscle

Back 46

GLUT2; GLUT4

Front 47

What happens to FAs made in the liver in response to excess glucose?

Back 47

Theyre esterified into triacylglycerides. The liver packages them with apoproteins --> VLDL.

The VLDL delivers its contents to fat and other tissues.

Front 48

How are triglycerides removed from VLDL?

Back 48

by an insulin-sensitive lipase called lipoprotein lipase (LPL) that lines the endothelial wall

Front 49

calories consumed as fat are immediately targeted to _____

Back 49

storage

Front 50

Lipids are packaged with apoproteins, particularly _________ into chylomicrons

Back 50

apoprotein C2

Front 51

How do chylomicrons leave the intestine?

Back 51

with the lymph, primarily via the thoracic duct, and are dumped into the venous circulation.

Front 52

Which rises more after a meal?
A) CHolesterol
B) Triglycerides

And why?

Back 52

Triglycerides. This is because chylomicrons don't contain much cholesterol.

Front 53

What hydrolyzes Triglycerides to free FAs and glycerol in chylomicrons? What happens then?

Back 53

LPL; Tissues then absorb the free FAs

Front 54

How is LPL activated?

Back 54

by attaching to the Apoprotein C2 that is part of chylomicron

Front 55

What produces LPL?

Back 55

adipocytes

Front 56

How does insulin affect LPL?

Back 56

increases snyhtesis and translocation of LPL from adipocyte to endothelial surface

Front 57

What processes does insulin
A) decrease
B) increase
in liver?

Back 57

A) Glycogenolysis; gluconeogenesis; ketogenesis

B) FA synthesis; glycogen synthesis

Front 58

What processes does insulin
A) increase
B) decrease
in adipose tissue?

Back 58

A) Glycerol synthesis; esterification of triglycerides (fat synthesis)

B) Lipolysis

Front 59

What processes does insulin
increase
in muscle?

Back 59

A) glucose uptake; glycogen synthesis; amino acid uptake and protein synthesis

Front 60

In the fasted state, ____ is single largest consumer of fuel

Back 60

brain (obligate glucose cnosumer)

Front 61

2 sources of fuel available to brain

Back 61

1) Ketoacids: By-products of FA metabolism (acetoacetate, hydroxybutyrate)

2) Glycogenolysis and gluconeogenesis from liver

Front 62

In states of prolonged fasting and type 1 DM, what provides energy to brain?

Back 62

ketoacids

Front 63

What hormones promote maintenance of normal glucose levels during fasting?

Back 63

increase in glucagon and decrease in insulin

Front 64

Glucagon is secreted by ___ cells in Islets of Langerhans

Back 64

alpha

Front 65

What is an emergency tx for unconscious diabetic?

Back 65

glucagon injection - quickly breaks down liver glycogen stores and stimulates release of glucose from the liver and restores circulating glucose levels

Front 66

3 steps to gluconeogenesis

Back 66

1) Delivery of substrates (lactate, alanine, glycerol) to liver

2) FAs are the substrates that produce the energy necessary to drive the process

3) Enzymes in gluconeogenic pathway need to be stimulated

Front 67

What are the substrates (lactate, alanine, glycerol) converted to in the liver for gluconeogenesis?

Back 67

pyruvate

Front 68

What does an increase in the glucagon/insulin ratio potentiate?

Back 68

Ketogenesis.

Front 69

Liprotein lipase recognies what apoprotein?

Back 69

Apo C2

Front 70

What are the coactivators of LPL?

Back 70

Apo C2, Insulin

Front 71

What is intermediate density lipoprotein? (IDL)

Back 71

VLDL after catabolism. Has less triglyceride and is cholesterol enriched. Approximately 50% is degraded by liver

Front 72

How does LDL form?

Back 72

While 50% of IDL (from VLDL) is degraded in the liver, the other half is stripped of triglycerides to mainly be cholesterol esters. This is LDL

Front 73

What protein do LDL receptors (found throughout the body) bind to?

Back 73

Apo B

Front 74

T/F LDL particles appear to have a vital function

Back 74

F. Yet, overproduction does much harm.