biochemistry question

[kyleman1]

I asked this earlier and never got a response. If anyone is good with biochem, i guess you can help me.

My question:
When muscles hypertrophy, how profound is the increase in your glut 4 insulin receptors? In terms of improving insulin sensitivity, is muscular hypertrophy the best option for someone who is insulin resistant?

Thanks
-Kyle

 

[imported_dkm1987]

From what I have read exercise training does not correct but compensates for the defects in muscle insulin resistance by increasing expression of GLUT4. Stimuli such as insulin and muscle contractions then cause the translocation of GLUT4 to the cell surface. This increase in GLUT4 protein is essential for the improvement in muscle insulin resistance.

The same cascading signals initiated to induce hypertrophy (MAPK) also play a role in GLUT 4 expression in the muscle cell surface. There are reviews on pubmed that delve deeply into this and some show a marked increase in expression during hypoxia stress while others show an increase during strain, so suffice it to say that both cascades can improve glucose uptake, but does having more muscle mass increase glucose uptake, I would believe yes. But I've been wrong before.

 

[kyleman1]

I would believe so too. The fact that another lb of muscle spells a use of another 50-100 calories would indicatet that the muscles are more metabolically active. And it would only make since for a tissue to increase its sensitivity to insulin because it needs extra energy now, which can be obtained from glucose! What do you think?

 

[imported_dkm1987]

Quote[/b] (kyleman1 @ April 06 2005,12:22)]I would believe so too. The fact that another lb of muscle spells a use of another 50-100 calories would indicatet that the muscles are more metabolically active. And it would only make since for a tissue to increase its sensitivity to insulin because it needs extra energy now, which can be obtained from glucose! What do you think?

Not disagreeing with you, cause I am not sure. Aaron or Bryan would be best to answer that. What I will say though is even though muscle is more metabolically active it can and does use other substrates for energy besides just glucose. So again it isn't something I have delved all that deep into, so I'll defer to those who know.