periph nerves; are they insulin sensitive?

[eatsleepmed]

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Ok guys, so I know some tissues like the CNS and RBCs can uptake glucose independently of insulin via GLUT1, but are peripheral nerves also included in that category?

Or are they insulin sensitive, i.e. bring in more glucose with insulin around?

THANKS!!

 

[Apoplexy__]

GLUT3 actually - a high-capacity, low-affinity isoform. It can suck in a ton of glucose, but only when serum levels start getting really high. If you were trying to explain diabetic neuropathy with the logic of GLUT1 transporters, the same logic applies in the case of the neurons having GLUT3.

http://ajpendo.physiology.org/content/295/2/E242

 

[sanj238]

GLUT3 actually - a high-capacity, low-affinity isoform. It can suck in a ton of glucose, but only when serum levels start getting really high. If you were trying to explain diabetic neuropathy with the logic of GLUT1 transporters, the same logic applies in the case of the neurons having GLUT3.

http://ajpendo.physiology.org/content/295/2/E242

I would be careful saying GLUT 3 is a low affinity transporter. It is actually a high affinity high capicity one. This is of key importance because GLUT 3 is essential for basal maintanance of glucose. That is glucose is constnatly uptaken regardless of hte amount available so that glucose is always transported even when there is low amounts. Its high vmax is key because even when there is maximal amount of glucose such as in a meal transport rate does not become limited (and become zero order).....

Glut 1 and 2 however are low affinity high vmax allowing for high levels of absorption of glucose during meal phase. DOnt confuse this with hexokinase and glucokinase which also have similar concepts but are about converting glucose that has been absorbed into g6p...

 

[eatsleepmed]

So it looks like that review mainly talks about GluT expression in cns/brain, which is where Glut3 (pretty much exclusively, except maybe some fast twitch muscle fibers) and Glut1 are found.
http://www.sciencedirect.com/science/article/pii/0006291X92923622

In terms of peripheral nerves - all the papers I can find say that Glut1 is mainly expressed in the peripheral nerves, which is insulin-insensitive.

Glut3 is insulin sensitive.
http://www.ncbi.nlm.nih.gov/pubmed/16337941

🙂

 

[Apoplexy__]

I would be careful saying GLUT 3 is a low affinity transporter.

Ah, sorry. I actually got what I said from Firecracker (a review site). Humorously enough, they actually used that exact hexokinase/glucokinase analogy. I thought I confirmed it in the article I linked to, but after a second look, I misread that source. Good to know.

So it looks like that review mainly talks about GluT expression in cns/brain, which is where Glut3 (pretty much exclusively, except maybe some fast twitch muscle fibers) and Glut1 are found.
http://www.sciencedirect.com/science/article/pii/0006291X92923622

In terms of peripheral nerves - all the papers I can find say that Glut1 is mainly expressed in the peripheral nerves, which is insulin-insensitive.

Glut3 is insulin sensitive.
http://www.ncbi.nlm.nih.gov/pubmed/16337941

Sorry #2. After not finding anything in FA or Goljan RR, a Google search said that GLUT3 was the "GLUT of the neurons" and my link said that GLUT3 was isolated from muscle cell neurons so I just hastily put two and two together. Glad you found your answer though.