Question

C. Duncan is a Caucasian male (age 14) that is brought to your attention because his family concerned about his inability to perform strenuous exercise. Duncan suffered severe muscle cramping during his P.E. classes but is normal if at doing routine physical activity or performing light to moderate exercise. A physical examination showed poorly developed muscle tissue, but his liver size was normal. A fasting glucose level check showed normal levels.

1. Duncan’s blood was also tested for alanine levels and showed a decrease in alanine after exercise, indicating that Duncan’s muscle cells were taking up alanine. In a normal individual, alanine levels would be expected to rise in the muscle during exercise.

Why would the alanine concentrations in the blood increase in a normal person?

How would you explain the alanine concentration results for Duncan’s test?

2. Explain why Duncan does not suffer from abnormal blood glucose levels.
   3. You suggest that perhaps Duncan should refrain from strenuous exercise. But if he cannot avoid it, what can you advise him to do during exercise to alleviate some of his suffering? Explain.

You decide that a genetic analysis is in order to discover the source of Duncan’s problems. Suggest at two gene sequences you would inspect, and what you would look for in these genes, to investigate the problem.

Answer 1

1. Normaly,protein is not an important energy fuel for exercising muscle.In spite of this,there is a significant inccrease in the rate of amino acid catabolism during exercise.With short term exercise, the transamination of glutamate by alanine aminotransferase leads to increased levels of alanine in muscle and plasma, and increase release of alanine from the muscle.At the same time ,the muscle and plasma glutamate concentration are markedly decreased.

2.Genrally,It is accepted that disturbed level of alanine concentration cause some liver disease.As for the long time they accept it as markeble of liver disease.But here on testing we get normal liver size ,so factor mainly effects abnormal level of glucose.Primary level of alanine introduce two type of diabetese,which distored it level.

3. In order to maintain strenuous exercise with control level of alanine, Duncan should cosume several glucotic supplements which enhance the level of alanine in suspect body.

4. While there are two isoforms of ALT,namely ALT1 and ALT2, when referring to the protein,we will use the ALT name.THe gene that encodes for the cyotosolic alanine aminotransminase 1 protein(ALT1), also known as glutamate -pyruvate transaminase 1(GPT1) is located in chromosome 8 and has 11 exons.ALT2 is encoded by a different gene (GPT2) located in chromosome 16. The GPT2 mRNA is expressed at high levels in muscle,kidney and brain and at lower levels in liver and breast.