Lecture 5

Question 1

Starvation

Answer 1

Begins at the start of the post-absorptive period when all food digested and no substrates coming in from gut.

Question 2

Rules

Answer 2

1. You need to keep [glucose]blood ~5mM
2. Brain cannot use glucose. FAs cannot cross blood brain barrier. Glucose uses GLUT-1
3. You cannot convert FA to carbs

Question 3

First few hours

Answer 3

During first few hours, tissues use glucose causing decrease BGLs. To prevent hypoglycyemia, liver releases glucose into bloodstream

Question 4

Branch points

Answer 4

Glycogen phosphorylase can only take glucose off if they are on the ends of branch. ‘Debranching enzyme’ cuts and pastes glucose. Branched glucose has different link than rest of chain. It is hydrolysed and released as glucose

Question 5

Muscles and glucogenolysis

Answer 5

Muscle does not break down much glycogen in starvation as it has no glycogen receptors, has no G6Pase therefore cannot convert G6P to glucose.

Question 6

White adipose tissue lipolysis

Answer 6

PKA phosphorylates hormone sensitive lipase and perilipin.