Lecture 8 - Protein Metabolism and Exercise

Question 1

It is quite easy to label…

Answer 1

plasma glucose - can differentiate from glycogen oxidation

Question 2

carbon 13 is stable but not…

Answer 2

radioactive (unlike carbon 14)

Question 3

During endurance exercise, all glucose that is taken up from the circulation is ______

Answer 3

oxidised

Question 4

Plasma glucose oxidation during exercise can also be determined by…

Answer 4

measuring the uptake of (6,6-2h2)-glucose

Question 5

The large majority of metabolism during high intensity comes from …

Answer 5

muscle glycogen

not much fat

Question 6

What do you measure AA oxidation?

Answer 6

Nitrogen balance, Plasma Urea, Urea in urine (very crude, no fine detail)

These measures only give a general idea

Question 7

Each AA has it’s own specific….

Answer 7

metabolism

Question 8

You should always use ______ AAs for tracing purposes

Answer 8

essential

Question 9

Glucose-Alanine Cycle involves:

Answer 9

Breakdown of Alanine to Pyruvate –> Glucose in the liver

once arrives at msucle can enter TCA cycle.

Alanine in the muscle can be transferred to the liver to provide an AA source for this process

Question 10

AAs can enter the TCA cycle at ______ points

Answer 10

different - all needed to keep the cycle going

Question 11

Oxidation rate of leucine is much higher than ____

Answer 11

phenalalanine - Oxidatioin rate of AAs is different

Question 12

Exercise increases leucine oxidation, but not _________ oxidation

Answer 12

phenylalanine oxidation - the oxidation rate of AAs is different

Question 13

What effect does exercise have on urea production

Answer 13

none - it does not increase

Protein intake has more profound effect on urea production than exercise

Question 14

Using beta-adrenergic blockage during exercise what happened?

Answer 14

Reduced FFA/Glycogen availability

reduced glycogen utilisation

**Increases Leucine oxidation

Question 15

under normal conditions the use of Leucine is.

Answer 15

suppressed by other fuels

Question 16

Availability of glycogen influences the use of leucine during exercise, however…

Answer 16

contribution to total energy expenditure remains very small

Question 17

Using stable isotope methodology we can …

Answer 17

assess plasma glucose and FFA oxidation and determine the contribution of the different substrate stores to energy expenditure

Question 18

In what way do AAs play a role in energy metabolism?

Answer 18

Each AA has its own specific metabolism

Glutamate is important to maintain TCA intermediates to allow maximal rates of FFA oxidation

Alanine is produced in muscle during exercise and transported to the liver for gluconeogenesis and urea production

Leucine, but not phenylalanine, oxidation is increased during exercise

Question 19

Name 3 essential AAs

Answer 19

Leucine, isoleucine, valine