Cardio 3

Question 1

What does white adipose tissue secrete and what does this signal by?

Answer 1

Leptin - ObR receptor via POMC

Question 2

What pathway does leptin activate?

Answer 2

JAK-STAT

Question 3

What does JAK-STAT lead to?

Answer 3

Cell growth and proliferation

Question 4

What does MAPK lead to?

Answer 4

Cell growth and differentiation

Question 5

What does PI3K lead to?

Answer 5

Growth, proliferation and differentiation

Question 6

What happens when megalin binds to leptin?

Answer 6

Signalling cascade

Question 7

What is the main perpetrator for increased BP associated with obesity?

Answer 7

Leptin

Question 8

What happens to leptin levels when on high fat diet?

Answer 8

Increase

Question 9

What does abnormal leptin signalling cause?

Answer 9

Obesity

Question 10

What happens if you change the leptin pathway?

Answer 10

No obesity associated hypertension

Question 11

What happens if the leptin concentration is restored?

Answer 11

Heart rate and hypertension increased

Question 12

What does leptin target in the brain?

Answer 12

DMH to regulate BP

Question 13

What happens if you turn off leptin signalling via leptin receptor?

Answer 13

Prevent increased BP

Question 14

Is leptin present in the urine in obesity?

Answer 14

No - kidneys able to process leptin

Question 15

What does leptin do to the glomerulus?

Answer 15

Alters it - increases TGF-B1 - increases collagen and fibrosis

Question 16

What happens when proximal tubule cells are exposed to more leptin?

Answer 16

More phosphorylated and active proteins - megalin signals by mTORC2 instead of JAK-STAT

Question 17

What proteins does the glomerulus filter?

Answer 17

Proteins less than 70kda - including albumin

Question 18

What % of albumin is filtered and reabsorbed?

Answer 18

0.06-3%, 96%

Question 19

What is the function of podocytes?

Answer 19

Allow selective passage of contents into the filtrate

Question 20

What is megalin?

Answer 20

Scavenger receptor in proximal tubule that binds to ligands

Question 21

What is the function of megalin?

Answer 21

Bring ligands into cell for degradation or transcytosis

Question 22

What does the amount of megalin determine?

Answer 22

The quantity of proteins that will be degraded

Question 23

What does meaglin do when cleaved by peptide transferases?

Answer 23

Acts as a signal transducer - regulates gene transcription

Question 24

What does AMPK do?

Answer 24

Regulates cell energy homeostasis

Question 25

What activates AMPK?

Answer 25

Leptin and adiponectin

Question 26

What does obesity do to AMPK?

Answer 26

Blocks it - increases inflammation

Question 27

What does activation of AMPK in type 2 diabetes prevent?

Answer 27

Renal hypertophy

Question 28

What does AMPK inhibition decrease?

Answer 28

TGF-B1 secretion

Question 29

What is AMPK the driver for, and what is this initiated by?

Answer 29

Fibrotic change - leptin binding to megalin

Question 30

Where is leptin secreted from and what is the normal plasma level?

Answer 30

Secreted from placenta, GIT, mammary epithelium

Normal concentration is 59.5ng/mL

Question 31

What is the direct action of leptin and why?

Answer 31

Increase BP - activation of nerves that supply CV system

Question 32

What does leptin up regulate in the proximal tubule cells?

Answer 32

ERK 1/2, AMPK, mTOR

Question 33

What % of Australians are obese?

Answer 33

63%

Question 34

How does leptin reduce metabolic activity?

Answer 34

mTOR