For discussing the functions of different structures of all organisms.
When sugar concentration of blood is high or when there is need of braking sugar for energy.... the insulin is secreated by Ilets of L.H. in pancreas and it binds to cells and sugar transport is activated..
Senior Education Officer, BNHS, India. www.bnhs.org
Who says reason for world war IV will be Petrol?
Reason lies in two words "Me and Mine".
GLUT4? I thought the only ones are GLUT1 and GLUT2. SO how many are there? And where are the others except 1 and 2 located?
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
you also have GLUT 3 and GLUT 5 with known functions. GLUT4 is the only insulin-dependant glucose transporter (although contraction in the muscle is the main trigger for GLUT4-expression)
They all belong to the same family, but all have different kinetic properties and thus are distributed in different tissues.
GLUT2: high Km --> thus never saturated under physiological conditions (that's why it's expressed in the liver and pancreas cells for glucose sensing and acting like a glucose sink in the liver and transport over the basolateral cell membrane in the small intestine)
GLUT3: low Km and thus very high affinity for glucose --> expressed in the brain, because it's saturated and thus keeps glucose transport into the brains constant till glucoseconcentration to 2 mM
--> the mechanism of how insulin triggers effects in the target cell is not yet completely understood. Probably it acts through the insulin recepotor phosporylating the insulin receptor substrates and then act via the PI3K-pathway.
i'm confused, i though glut 1 was in the brain? are they both in the brain? and where is glut 4 located?
yeah, i've looked it up on wikipedia. but it's easier to ask someone else...
Anyway thank you for taking the time to explain it for me sdekivit
i have a very good book about the metabolic regulation:
metabolic regulation: a human perspective by Frayn.
GLUT4 is located in the adipose tissue and the striated muscle --> thus these tissues will take up glucose under influence of insulin
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