Cellular Uptake of Glucose. –80-110 mg/dl euglycemia –< 45 mg/dl hypoglycemia –> 150-200...
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Transcript of Cellular Uptake of Glucose. –80-110 mg/dl euglycemia –< 45 mg/dl hypoglycemia –> 150-200...
– 80-110 mg/dl euglycemia
– < 45 mg/dl hypoglycemia
– > 150-200 mg/dl after CHO meal (ie, below Tmax)
– > 300-600 mg/dl uncontrolled diabetes
Cellular Uptake of Glucose1.) Gradient usually exists ECF>ICF (HK keeps ICF low)
2.) Glucose is polar, therefore is hydrophilicFacilitated diffusion occurs via 5 glucose transporters GLUT 1 GLUT 5
Annimation of Glucose uptake
– Based on concentration gradient
Cellular Uptake of Glucose3.) Unregulated glucose uptake
– GLUT 1, 2, 3 & 5 (liver, neurons, RBC, kidney)4.) Regulated glucose uptake
– Insulin on GLUT 4 (muscle, adipose)
5.) Insulin -- Pancreas cells & Chains– 3 disulfide bondsInsulin receptor -- membrane 4 subunits GLUT 4 translocation fromintracellular storage sites to membrane glucose
uptake 10-20x within 5 min.
InsulinA chain 21AA
B chain 30AAS
S SS
Insulin Receptor
S S
B Subunits
A Subunits
Tyrosine Kinase (Autophosphorylate)
Fully active Tyrosine Kinase now can phosphorylate (activate/deactivate) intracellular enzymes
Activates PDE cAMP
activates PP-1 / dephosphorylates GS and PKA
EPI inhibits insulin receptor and release