Integrative Metabolism

Question 1

Function of Adipose tissue

Answer 1

Energy storage - TAG droplets (83% of total energy)
Protection - cushioning of organs
Hormone Production
Insulation
Thermogenics

Question 2

Leptin

Answer 2

An Adipokine

Mediates appetite supression
Regulates AMP Kinase

Induces expression of uncoupling protein in inner mitochondrial membrane which results in dissipation of the proton gradient - produces heat

Leptin resistance contributes to insulin resistance resulting in hyperglycemia

Question 3

AMP Kinase

Answer 3

regulates fuel metabolism by phosphorylation of substrates

Turns on Catabolism (eg: beta oxidation)
Turns off Anabolism (eg: TAG, glycogen synthesis)

-Leptin leads to more subtle activation of AMP Kinase

Question 4

Creatine Phospate

Answer 4

Formed in muscle when ATP levels are high. Used as a storage form of ATP.

When exercising the muscle uses ATP. Creatine Phosphate will then drive ATP synthesis for use by muscles.

Question 5

Type I muscle fibers

Answer 5

Slow twitch

Slow ATP hydrolysis
Slow contraction speed
Low glycolitic capacity'
Low Glycogen storage
High Oxidative capacity
Good blood supply

Question 6

Type IIa muscle fibers

Answer 6

Fast Oxidative

Fast ATP Hydrolysis
Fast contraction speed
Moderate glycolitic capacity
Moderate Glycogen storage
Moderate Oxidative capacity - fewer mitochondria
Moderate blood supply

Question 7

Type IIb muscle fibers

Answer 7

Fast twitch

Fast ATP Hydrolysis
Fast contraction speed
High glycolitic capacity
High Glycogen storage
Low oxidative capacity - fewwer mitochondria
Poor blood supply

Question 8

TAG Synthesis

Answer 8

Glycerol 3 -P to Phosphatidate via acyltransferase (adds 2 Acyl groups)

Phosphatidate to DAG via Phosphatase

DAG to TAG via acyltransferase (adds 1 acyl group)

Question 9

Fed State in adipose tissue

Answer 9

Insulin promotes Increased glucose in cell due to GLUT 4 receptors

Insulin promotes increased LPL synthesis and secretion by adipocytes resulting in increased FA in adipose cells

Glucose converted to DHAP then to Glycerol 3-P
FA converted to FA CoA.

The two combine in TAG synthesis

Question 10

Fasting state in adipose tissue

Answer 10

Hydrolysis of TAGs via Hormone Sensitive Lipase (HSL) which is activated (phosphrylated) by Epinephrine, and by the decrease of insulin

Question 11

TAG mobilization

Answer 11

1. Low insulin / high glucagon, (epinephrine)
2. Elevated cAMP
3. Activated PKA
4. Phosphorylation and activation of Hormone Sensitive Lipase (HSL)
5. Activation of lipolysis

FA released for energy use in the body - carried in the blood via albumin.

Glycerol transported to the liver and converted to glycerol 3-P for gluconeogenesis

Question 12

Neurotransmitter precursors:
Catacholamines
Serotonin
Histamine
GABA

Answer 12

Tyrosine
Tryptophan
Histadine
Glutamate

*require some form of AA decarboxilation reaction using PLP as a cofactor

Question 13

Epilepsy

Answer 13

Low GABA

Treated with GABA analogs or drugs that block GABA reuptake from synapse

Question 14

Benzodiazepines

Answer 14

(e.g. valium) bind to the GABA receptor –potentiates GABA → reduced anxiety