Absorptive State

Question 1

1. What is the fate of glucose in the liver, muscle, adipose tissue, and other tissues?
2. What is the fate of amino acids in the liver and muscle?
3. What is the fate of triglycerides in adipose tissue?

Answer 1

1. liver = glycogen, TG in XS
muscle = glycogen
adipose = TG
other = Krebs cycle for energy
2. liver = ketoacids for energy
muscle = protein
3. hydrolysed into free fatty acids and glycerol, reesterified back into fat

Question 2

Control of absorptive state:

1. Switch from post absorptive to absorptive state due to increased ………. and ……….. in blood
2. Insulin - secreted by …….. ……. . Trigger is …………..and ………. ………..
3. ……….. is the transporter responsible for Bcell glucose uptake. This triggered the generation of …… from glucose metabolism and …… influx.
4. The raised intracellular …… causes insulin exocytosis

Answer 2

1. glucose and insulin
2. bcells, glucose and AA’s
3. GLUT2, ATP, Ca2+
4. Ca2+

Question 3

By what transporter is glucose taken up in cells?

Answer 3

GLUT-4

Question 4

What are the effects of insulin on:
- liver
- adipose
- muscle 
What are the transporters involved?

Answer 4

Liver = GLUT-2 (insulin insensitive), inhibits glycogenolysis, stimulates glycogen synthesis, drives lipogenesis if XS glucose
Muscle = GLUT-4 (insulin sensitive), recruitment of GLUT-4, stimulates glycogen synthesis, promoting protein synthesis
Adipocytes = recruitment of GLUT-4, promote lipogenesis, inhibits lipolysis, increases the synthesis of lipoprotein lipase (acts on chylomicron to release fatty acids)

Question 5

What 2 parts make up the post-absoptive state? Which is the most important?

Answer 5

1. glucose-supplying reactions - generate glucose

2. glucose sparing reactions - generate other substrates such as FA’s and ketone bodies MORE IMPORTANT

Question 6

What are the 2 glucose supplying reactions?

Answer 6

glycogenolysis

gluconeogenesis

Question 7

What 3 things can go to the liver to produce glucose? Where do they come from?

Answer 7

amino acids - muscle
lactate - muscle
glycerol - adipose

Question 8

What is the main regulator of glucose-supplying reactions?

What 4 hormones can affect it?

Answer 8

fall in insulin levels
epinephrine, increases glycogen breakdown
glucagon, increase glycogen breakdown
cortisol, increases gluconeogenesis, decreases glucose uptake
growth hormone, decreases glucose uptake

Question 9

What happens in a type 1 diabetic in:

• liver
• adipocytes
• muscles

Answer 9

liver = decreased glycogen synthesis, increased glycogenolysis, ketone bodies formed
adipocytes = decreased glucose uptake, increased lipolysis 
muscles = increased extracellular glucose, breakdown of protein to amino acids as substrate for gluconeogenesis

Question 10

Summary of metabolic derangement:

• level of glucose in blood is high because …… is not stimulated
• further compounded by lack of insulin mediated inhibition of ……… and ………….

Answer 10

uptake
glycogenolysis
lipolysis

Question 11

Describe the consequences of increased lipolysis in diabetics, in a series of events.

Answer 11

lipolysis –> FFA go to liver –> beta oxidation –> XS acetyl CoA –> Krebs inhibited –> ketogenesis –> acidosis

Question 12

Clinical features of uncontrolled diabetes?

Answer 12

polyuria/polydipsia
dehydration
blurred vision
infections e.g. thrush
weight loss
ketosis
confusion
coma

Question 13

What can happen to diabetics when treated rapidly with insulin?

Answer 13

hypokaleamia

Question 14

What are the 2 categories of long-term metabolic consequences of diabetes?

Answer 14

microvascular
- retinopathy, nephropathy, neuropathy
macrovascular
- atherosclerosis, strokes, heart attacks, peripheral vascular disease