Skildum's glucose metabolism; 3.18

Question 1

What does a hypoglycemic hormone do?

Answer 1

Signal for glucose to be removed FROM blood

Question 2

What is an example of a hypoglycemic hormone?

Answer 2

Insulin

Question 3

What does a hyperglycemic hormone do?

Answer 3

Signal for glucose to be secreted INTO blood

Question 4

What are some examples of hyperglycemic hormones?

Answer 4

Glucagon**

Glucocorticoids and catecholamines

Question 5

Which protein in the proximal tubule reabsorbs the bulk of the glucose that gets filtered through the glomerulus?

Answer 5

SGLT-2 accounts for 90% of the reabsorbed glucose (it has a higher Kd, or lower affinity, than SGLT-1)

Question 6

Where is SGLT-2 in the tubule?

Answer 6

S1/S2 segments of the proximal tubule (1st 2/3 of proximal tubule)

Question 7

What enzyme is found in the liver, but not muscle, that allows for glucose transportation?

Answer 7

Glucose-6-phosphatase

Question 8

Glucose-6-phosphatase is down regulated by insulin. What other enzyme is down regulated by insulin?

Answer 8

PEP carboxykinase

Question 9

How are G6P and PEP carboxykinase regulated by insulin?

Answer 9

Insulin activates a receptor tyrosine kinase → Phosphatidyl inositol 3-kinase activation → PIP-3 → activation of PDK1 → activation of PKB → phosphorylation of intracellular targets (FOX01 and CRTC2) → decreased (no?) transcription