Glucose Metabolism Review

Question 1

How do insulin and glucagon affect hepatic glycolysis

Answer 1

insulin increases hepatic glycolysis

glucagon decreases hepatic glycolysis

Question 2

Pathway for insulin secretion from β-cells

Answer 2

Glc enters via GLUT-2
Glc --> ATP
ATP inhibits K+ channel
depolarization of cell
VG Ca2+ channels open
exocytosis of insulin granules

Question 3

Glucagon actives this phosphorylating enzyme

Answer 3

PKA via cAMP ie adenylate cyclase

Question 4

PKA from glucagon pathway activates which enzyme for hepatic gluconeogenesis

Answer 4

CREB –> CREB-P

CREB-P moves to nucleus, binds PGC1α

Question 5

CREB-P – PGC1α complex from glucagon pathway

action

Answer 5

expression of PEPCK and G6Pase

necessary for hepatic gluconeogenesis

Question 6

How do glucagon and insulin affect hepatic gluconeogenesis

Answer 6

glucagon: increases via PCPCK and G6Pase expression via PKA and CREB-PGC1α pathway
insulin: decreases via PKB pathway inhibiting FOX01, inhibits G6P and PEPCK expression

Question 7

Control of glucagon secretion

Answer 7

insulin controls secretion of glucagon from α-cells

Question 8

Functions of:
PFK1
PFK2

Answer 8

PFK1: F6P –> F-1,6-BP –> glycolysis
PFK2: F6P –> F-2,6-BP –> activation of PFK1
*PFK2 makes F-2,6-BP to tell PFK1 to hurry the hell up and do more glycolysis
*if PFK2 isn’t active, then FBPase-2 is, which converts F-2,6-BP back to F6P fore conversion back to gluconeogenic substrate

Question 9

Gluconeogenesis from what substrates in fasting state

Answer 9

proteins

lactate

Question 10

Metformin mechanism

Answer 10

decreases adenylate cyclase activity

• actives LKB1, which
• activates AMPK, which
• phosphorylates TORC2, preventing nuclear localization

Question 11

Salicylate mechanism

Answer 11

uncouples mitochondria

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