The Benefits of Exercise on Glucose Transport

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The Benefits of Exercise on Glucose Transport

• By Jennifer Shoup, Emily Olson, Claire
  Hilsinger, Alicia Faubion, and
• Sierra Urie

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The Problem

• In society today diabetes is a major health
  concern.
• Diabetes is on the rise in every age group,
  including in children and young adults.
• Complications from diabetes and poor management
  of the disease can be life threatening.

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The Problem

• So what can diabetics do to improve their bodys
  use of glucose when they lack insulin or are
  insulin resistant?
• EXERCISE!!!
• Muscle cells can apparently import glucose
  without the use of insulin!
• HOW?

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What is GLUT-4?

• A carrier protein, found in adipocyte and muscle
  cell membranes
• Glucose transporter often regulated by insulin
• A GLUT-4 channel is the only mechanism which
  allows glucose to enter the cell
• GLUT-4 allows for facilitated diffusion

GLUT-4
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What triggers GLUT-4 translocation?

• Review Homeostatic mechanism involving insulin
  (pancreas)
• Insulin binds to tyrosine kinase receptors, which
  activate multiple second messenger pathways
• enzymes
• transport activity

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What triggers GLUT-4?

• Contractions in muscle cells stimulate the
  transcription and translation of the genes to
  produce more GLUT-4 gates
• Muscle contractions cause the release of Ca2
  into the sarcoplasm.
• Excess Ca2 and decreased inorganic phosphate
  inside the cell seem to trigger the translocation
  of GLUT-4 vesicles to the cell membrane.

short lived (40-80hrs after exercise) regular
exercise is key
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Intracellular Ca2 may activate PKC

• Hypothesized insulin-independent pathway to move
  GLUT-4 to the cell membrane.

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Why does the insulin independent mechanism exist?

• Muscles need access to energy, even when insulin
  is not present to assist in transporting glucose
• ANALOGY
• House there is more than one entry which is like
  having more than one mechanism to trigger GLUT-4
  gates.
• The key to the front door is insulin, and the key
  to the back door is muscle contraction.
• If you lost the keys to the front door, you can
  still get into the house.

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