Insulin on Muscle Flashcards Preview

Regulatory Physiology and Pharmacology > Insulin on Muscle > Flashcards

Flashcards in Insulin on Muscle Deck (31):
1

What are the types of glucose transporter?

SGLT
GLUTs

2

How many TM domains does the SGLT have?

14

3

What part of the SGLT binds the sugar?

C-terminus

4

How does the SGLT work?

Na binds a negative charge in the transporter, opens up for glucose, glucose binds causing conformational change and the release of glucose and Na on the other side

5

What are the transporters on the basolateral membrane of the gut?

Na-K ATPase
GLUT2

6

What are the features of GLUTs?

present on the surface of all cell membranes
transport glucose down a concentration gradient
energy dependent process
can operate bi-directionally as long as down the gradient

7

What are the classes of GLUTs?

Class I
Class II
Class III

8

What are the features of the gluts in class I?

1,3,4 are all high affinity
2 is low affinity
they all transport glucose

9

What are the features of the gluts in class II?

5,7,9,11 and HMIT1
low affinity for glucose, transport fructose

10

What are the features of the gluts in class III?

6,8,10,12
not really sure yet

11

How many TM domains do GLUTs have?

12

12

Where is GLUT1 generally found?

ubiquitously

13

Where is GLUT2 generally found?

kidney, sm. intesting, liver, pancreatic b cells

14

Where is GLUT 3 found?

neurons and placenta

15

Where is GLUT 4 found?

skeletal muscle, cardiac muscle, adipose tissue

16

Where is GLUT 4 found?

skeletal muscle, cardiac muscle, adipose tissue

17

What is GLUT4 responsible for?

the response to insulin

18

What is cytochalasin B?

a fungal metabolite called CB which binds to GLUTs in a non-competitive manner

19

What is useful about CB?

It gives you a 1:1 molar ratio to the number of transporters present

20

What can be observed with insulin treatment?

translocation of transporters from the Intracellular membrane to the plasma membrane

21

How can the translocating transporter be identified?

with antibodies and GFP

22

Why is this finding important?

muscle is the principal tissue for glucose use in the fed state
muscle is a primary target of insulin
muscle must be fully responsive to insulin in order to lower blood glucose

23

What does phosphorylation of the insulin receptor cause?

phosphorylation of docking proteins such as IRS-1,2,3,4

24

What does phosphorylation of docking proteins cause?

activation of signalling pathways PI3K, PKB, MAPK, p70S6

25

What does activation of the signalling pathways cause?

glucose transport, glycogen synthesis, lipogenesis, protein synthesis, gene expression, cellular growth

26

What does Insulin cause in muscle?

increase glucose up take
increase glucose use -> glycogen and glycolysis
increase amino acid uptake
increase protein synthesis, decreased protein breakdown

27

What is the skeletal muscle glucose uptake during exercise regulated by?

glucose supply, glucose transport
glucose phosphorylation

28

How does glucose phosphorylation maintain the concentration gradient?

It cannot exit the cell, so glucose can keep coming in

29

How does exercise simulate the effects of insulin?

increases the translocation of GLUT 4 via AMPK

30

What does Metformin do?

suppresses hepatic glucose production
increases muscle glucose uptake
inhibits complex 1 of respiratory chain

31

What shares the metabolic effect of Metformin?

AICAR